parent
bb670a2ceb
commit
8b92c3fdbe
@ -1,12 +1,11 @@
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/**
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*
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*/
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package heaps;
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package Heaps;
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/**
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* @author Nicolas Renard
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* Exception to be thrown if the getElement method is used on an empty heap.
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*
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*/
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@SuppressWarnings("serial")
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public class EmptyHeapException extends Exception {
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@ -1,4 +1,4 @@
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package heaps;
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package Heaps;
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/**
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* Interface common to heap data structures.<br>
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@ -10,32 +10,31 @@ package heaps;
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* max-heap).</p>
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* <p>All heap-related operations (inserting or deleting an element, extracting the min or max) are performed in
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* O(log n) time.</p>
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*
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* @author Nicolas Renard
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*
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*
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*/
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public interface Heap {
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/**
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*
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* @return the top element in the heap, the one with lowest key for min-heap or with
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* the highest key for max-heap
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* @throws Exception if heap is empty
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* @throws EmptyHeapException if heap is empty
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*/
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public abstract HeapElement getElement() throws EmptyHeapException;
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HeapElement getElement() throws EmptyHeapException;
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/**
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* Inserts an element in the heap. Adds it to then end and toggle it until it finds its
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* right position.
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*
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* @param element an instance of the HeapElement class.
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*/
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public abstract void insertElement(HeapElement element);
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void insertElement(HeapElement element);
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/**
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* Delete an element in the heap.
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*
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* @param elementIndex int containing the position in the heap of the element to be deleted.
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*/
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public abstract void deleteElement(int elementIndex);
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void deleteElement(int elementIndex);
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}
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@ -1,7 +1,7 @@
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/**
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*
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*/
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package heaps;
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package Heaps;
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import java.lang.Double;
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import java.lang.Object;
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@ -12,8 +12,8 @@ import java.lang.Object;
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* or double, either primitive type or object) and any kind of IMMUTABLE object the user sees fit
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* to carry any information he/she likes. Be aware that the use of a mutable object might
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* jeopardize the integrity of this information. </p>
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* @author Nicolas Renard
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*
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* @author Nicolas Renard
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*/
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public class HeapElement {
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private final double key;
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@ -22,7 +22,6 @@ public class HeapElement {
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// Constructors
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/**
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*
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* @param key : a number of primitive type 'double'
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* @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
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* additional information of use for the user
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@ -33,7 +32,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of primitive type 'int'
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* @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
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* additional information of use for the user
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@ -44,7 +42,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of object type 'Integer'
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* @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
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* additional information of use for the user
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@ -55,7 +52,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of object type 'Double'
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* @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
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* additional information of use for the user
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@ -66,7 +62,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of primitive type 'double'
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*/
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public HeapElement(double key) {
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@ -75,7 +70,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of primitive type 'int'
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*/
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public HeapElement(int key) {
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@ -84,7 +78,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of object type 'Integer'
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*/
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public HeapElement(Integer key) {
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@ -93,7 +86,6 @@ public class HeapElement {
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}
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/**
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*
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* @param key : a number of object type 'Double'
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*/
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public HeapElement(Double key) {
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@ -102,12 +94,14 @@ public class HeapElement {
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}
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// Getters
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/**
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* @return the object containing the additional info provided by the user.
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*/
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public Object getInfo() {
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return additionalInfo;
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}
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/**
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* @return the key value of the element
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*/
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@ -118,10 +112,10 @@ public class HeapElement {
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// Overridden object methods
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public String toString() {
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return "Key: " + key + " - " +additionalInfo.toString();
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return "Key: " + key + " - " + additionalInfo.toString();
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}
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/**
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*
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* @param otherHeapElement
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* @return true if the keys on both elements are identical and the additional info objects
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* are identical.
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@ -1,4 +1,4 @@
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package heaps;
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package Heaps;
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import java.util.ArrayList;
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import java.util.List;
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@ -6,15 +6,15 @@ import java.util.List;
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/**
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* Heap tree where a node's key is higher than or equal to its parent's and lower than or equal
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* to its children's.
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* @author Nicolas Renard
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*
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* @author Nicolas Renard
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*/
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public class MaxHeap implements Heap {
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private final List<HeapElement> maxHeap;
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public MaxHeap(List<HeapElement> listElements) throws Exception {
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maxHeap = new ArrayList<HeapElement>();
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public MaxHeap(List<HeapElement> listElements) {
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maxHeap = new ArrayList<>();
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for (HeapElement heapElement : listElements) {
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if (heapElement != null) insertElement(heapElement);
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else System.out.println("Null element. Not added to heap");
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@ -22,9 +22,15 @@ public class MaxHeap implements Heap {
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if (maxHeap.size() == 0) System.out.println("No element has been added, empty heap.");
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}
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// Get the element at a given index. The key for the list is equal to index value - 1
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/**
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* Get the element at a given index. The key for the list is equal to index value - 1
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*
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* @param elementIndex index
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* @return heapElement
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*/
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public HeapElement getElement(int elementIndex) {
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if ((elementIndex <= 0) && (elementIndex > maxHeap.size())) throw new IndexOutOfBoundsException("Index out of heap range");
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if ((elementIndex <= 0) || (elementIndex > maxHeap.size()))
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throw new IndexOutOfBoundsException("Index out of heap range");
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return maxHeap.get(elementIndex - 1);
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}
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// Toggle an element up to its right place as long as its key is lower than its parent's
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private void toggleUp(int elementIndex) {
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double key = maxHeap.get(elementIndex - 1).getKey();
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while (getElementKey((int) Math.floor(elementIndex/2)) < key) {
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swap(elementIndex, (int) Math.floor(elementIndex/2));
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elementIndex = (int) Math.floor(elementIndex/2);
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while (getElementKey((int) Math.floor(elementIndex / 2)) < key) {
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swap(elementIndex, (int) Math.floor(elementIndex / 2));
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elementIndex = (int) Math.floor(elementIndex / 2);
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}
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}
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// than any of its children's
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private void toggleDown(int elementIndex) {
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double key = maxHeap.get(elementIndex - 1).getKey();
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boolean wrongOrder = (key < getElementKey(elementIndex*2)) || (key < getElementKey(Math.min(elementIndex*2, maxHeap.size())));
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while ((2*elementIndex <= maxHeap.size()) && wrongOrder) {
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boolean wrongOrder = (key < getElementKey(elementIndex * 2)) || (key < getElementKey(Math.min(elementIndex * 2, maxHeap.size())));
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while ((2 * elementIndex <= maxHeap.size()) && wrongOrder) {
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// Check whether it shall swap the element with its left child or its right one if any.
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if ((2*elementIndex < maxHeap.size()) && (getElementKey(elementIndex*2 + 1) > getElementKey(elementIndex*2))) {
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swap(elementIndex, 2*elementIndex + 1);
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elementIndex = 2*elementIndex + 1;
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if ((2 * elementIndex < maxHeap.size()) && (getElementKey(elementIndex * 2 + 1) > getElementKey(elementIndex * 2))) {
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swap(elementIndex, 2 * elementIndex + 1);
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elementIndex = 2 * elementIndex + 1;
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} else {
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swap(elementIndex, 2 * elementIndex);
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elementIndex = 2 * elementIndex;
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}
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else {
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swap(elementIndex, 2*elementIndex);
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elementIndex = 2*elementIndex;
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}
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wrongOrder = (key < getElementKey(elementIndex*2)) || (key < getElementKey(Math.min(elementIndex*2, maxHeap.size())));
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wrongOrder = (key < getElementKey(elementIndex * 2)) || (key < getElementKey(Math.min(elementIndex * 2, maxHeap.size())));
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}
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}
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} catch (EmptyHeapException e) {
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e.printStackTrace();
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}
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if ((elementIndex > maxHeap.size()) && (elementIndex <= 0)) throw new IndexOutOfBoundsException("Index out of heap range");
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if ((elementIndex > maxHeap.size()) || (elementIndex <= 0))
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throw new IndexOutOfBoundsException("Index out of heap range");
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// The last element in heap replaces the one to be deleted
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maxHeap.set(elementIndex - 1, getElement(maxHeap.size()));
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maxHeap.remove(maxHeap.size());
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// Shall the new element be moved up...
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if (getElementKey(elementIndex) > getElementKey((int) Math.floor(elementIndex/2))) toggleUp(elementIndex);
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if (getElementKey(elementIndex) > getElementKey((int) Math.floor(elementIndex / 2))) toggleUp(elementIndex);
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// ... or down ?
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else if (((2*elementIndex <= maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex*2))) ||
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((2*elementIndex < maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex*2)))) toggleDown(elementIndex);
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else if (((2 * elementIndex <= maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex * 2))) ||
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((2 * elementIndex < maxHeap.size()) && (getElementKey(elementIndex) < getElementKey(elementIndex * 2))))
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toggleDown(elementIndex);
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}
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@Override
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throw new EmptyHeapException("Heap is empty. Error retrieving element");
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}
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}
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}
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@ -1,7 +1,7 @@
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/**
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*
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*/
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package heaps;
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package Heaps;
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import java.util.ArrayList;
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import java.util.List;
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@ -9,15 +9,15 @@ import java.util.List;
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/**
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* Heap tree where a node's key is higher than or equal to its parent's and lower than or equal
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* to its children's.
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* @author Nicolas Renard
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*
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* @author Nicolas Renard
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*/
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public class MinHeap implements Heap {
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private final List<HeapElement> minHeap;
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public MinHeap(List<HeapElement> listElements) throws Exception {
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minHeap = new ArrayList<HeapElement>();
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public MinHeap(List<HeapElement> listElements) {
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minHeap = new ArrayList<>();
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for (HeapElement heapElement : listElements) {
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if (heapElement != null) insertElement(heapElement);
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else System.out.println("Null element. Not added to heap");
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@ -27,7 +27,8 @@ public class MinHeap implements Heap {
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// Get the element at a given index. The key for the list is equal to index value - 1
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public HeapElement getElement(int elementIndex) {
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if ((elementIndex <= 0) && (elementIndex > minHeap.size())) throw new IndexOutOfBoundsException("Index out of heap range");
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if ((elementIndex <= 0) || (elementIndex > minHeap.size()))
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throw new IndexOutOfBoundsException("Index out of heap range");
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return minHeap.get(elementIndex - 1);
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}
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// Toggle an element up to its right place as long as its key is lower than its parent's
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private void toggleUp(int elementIndex) {
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double key = minHeap.get(elementIndex - 1).getKey();
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while (getElementKey((int) Math.floor(elementIndex/2)) > key) {
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swap(elementIndex, (int) Math.floor(elementIndex/2));
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elementIndex = (int) Math.floor(elementIndex/2);
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while (getElementKey((int) Math.floor(elementIndex / 2)) > key) {
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swap(elementIndex, (int) Math.floor(elementIndex / 2));
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elementIndex = (int) Math.floor(elementIndex / 2);
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}
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}
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@ -56,18 +57,17 @@ public class MinHeap implements Heap {
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// than any of its children's
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private void toggleDown(int elementIndex) {
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double key = minHeap.get(elementIndex - 1).getKey();
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boolean wrongOrder = (key > getElementKey(elementIndex*2)) || (key > getElementKey(Math.min(elementIndex*2, minHeap.size())));
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while ((2*elementIndex <= minHeap.size()) && wrongOrder) {
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boolean wrongOrder = (key > getElementKey(elementIndex * 2)) || (key > getElementKey(Math.min(elementIndex * 2, minHeap.size())));
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while ((2 * elementIndex <= minHeap.size()) && wrongOrder) {
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// Check whether it shall swap the element with its left child or its right one if any.
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if ((2*elementIndex < minHeap.size()) && (getElementKey(elementIndex*2 + 1) < getElementKey(elementIndex*2))) {
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swap(elementIndex, 2*elementIndex + 1);
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elementIndex = 2*elementIndex + 1;
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if ((2 * elementIndex < minHeap.size()) && (getElementKey(elementIndex * 2 + 1) < getElementKey(elementIndex * 2))) {
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swap(elementIndex, 2 * elementIndex + 1);
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elementIndex = 2 * elementIndex + 1;
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} else {
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swap(elementIndex, 2 * elementIndex);
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elementIndex = 2 * elementIndex;
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}
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else {
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swap(elementIndex, 2*elementIndex);
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elementIndex = 2*elementIndex;
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}
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wrongOrder = (key > getElementKey(elementIndex*2)) || (key > getElementKey(Math.min(elementIndex*2, minHeap.size())));
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wrongOrder = (key > getElementKey(elementIndex * 2)) || (key > getElementKey(Math.min(elementIndex * 2, minHeap.size())));
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}
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}
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@ -93,15 +93,17 @@ public class MinHeap implements Heap {
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} catch (EmptyHeapException e) {
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e.printStackTrace();
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}
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if ((elementIndex > minHeap.size()) && (elementIndex <= 0)) throw new IndexOutOfBoundsException("Index out of heap range");
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if ((elementIndex > minHeap.size()) || (elementIndex <= 0))
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throw new IndexOutOfBoundsException("Index out of heap range");
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// The last element in heap replaces the one to be deleted
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minHeap.set(elementIndex - 1, getElement(minHeap.size()));
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minHeap.remove(minHeap.size());
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// Shall the new element be moved up...
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if (getElementKey(elementIndex) < getElementKey((int) Math.floor(elementIndex/2))) toggleUp(elementIndex);
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if (getElementKey(elementIndex) < getElementKey((int) Math.floor(elementIndex / 2))) toggleUp(elementIndex);
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// ... or down ?
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else if (((2*elementIndex <= minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex*2))) ||
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((2*elementIndex < minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex*2)))) toggleDown(elementIndex);
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else if (((2 * elementIndex <= minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex * 2))) ||
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((2 * elementIndex < minHeap.size()) && (getElementKey(elementIndex) > getElementKey(elementIndex * 2))))
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toggleDown(elementIndex);
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}
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@Override
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@ -1,13 +1,13 @@
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package Heaps;
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/* Minimum Priority Queue
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* It is a part of heap data structure
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* A heap is a specific tree based data structure
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* in which all the nodes of tree are in a specific order.
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* that is the children are arranged in some
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* respect of their parents, can either be greater
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* or less than the parent. This makes it a min priority queue
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* or max priority queue.
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*/
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* It is a part of heap data structure
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* A heap is a specific tree based data structure
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* in which all the nodes of tree are in a specific order.
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* that is the children are arranged in some
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* respect of their parents, can either be greater
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* or less than the parent. This makes it a min priority queue
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* or max priority queue.
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*/
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// Functions: insert, delete, peek, isEmpty, print, heapSort, sink
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@ -1,12 +1,11 @@
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import java.util.Scanner;
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/**
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*
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* @author Afrizal Fikri (https://github.com/icalF)
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*
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* @author Libin Yang (https://github.com/yanglbme)
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*/
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public class LongestIncreasingSubsequence {
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public static void main(String[] args) throws Exception {
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public static void main(String[] args) {
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Scanner sc = new Scanner(System.in);
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int n = sc.nextInt();
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@ -20,7 +19,7 @@ public class LongestIncreasingSubsequence {
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}
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private static int upperBound(int[] ar, int l, int r, int key) {
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while (l < r-1) {
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while (l < r - 1) {
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int m = (l + r) / 2;
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if (ar[m] >= key)
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r = m;
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@ -37,7 +36,9 @@ public class LongestIncreasingSubsequence {
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return 0;
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int[] tail = new int[N];
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int length = 1; // always points empty slot in tail
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// always points empty slot in tail
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int length = 1;
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tail[0] = array[0];
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for (int i = 1; i < N; i++) {
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@ -47,14 +48,14 @@ public class LongestIncreasingSubsequence {
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tail[0] = array[i];
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|
||||
// array[i] extends largest subsequence
|
||||
else if (array[i] > tail[length-1])
|
||||
else if (array[i] > tail[length - 1])
|
||||
tail[length++] = array[i];
|
||||
|
||||
// array[i] will become end candidate of an existing subsequence or
|
||||
// Throw away larger elements in all LIS, to make room for upcoming grater elements than array[i]
|
||||
// (and also, array[i] would have already appeared in one of LIS, identify the location and replace it)
|
||||
else
|
||||
tail[upperBound(tail, -1, length-1, array[i])] = array[i];
|
||||
tail[upperBound(tail, -1, length - 1, array[i])] = array[i];
|
||||
}
|
||||
|
||||
return length;
|
||||
|
@ -1,16 +1,14 @@
|
||||
/*
|
||||
@author : Mayank K Jha
|
||||
/**
|
||||
* @author Mayank K Jha
|
||||
*/
|
||||
|
||||
*/
|
||||
|
||||
import java.io.IOException;
|
||||
import java.util.Arrays;
|
||||
import java.util.Scanner;
|
||||
import java.util.Stack;
|
||||
|
||||
public class Dijkshtra {
|
||||
|
||||
public static void main(String[] args) throws IOException {
|
||||
public static void main(String[] args) {
|
||||
Scanner in = new Scanner(System.in);
|
||||
|
||||
// n = Number of nodes or vertices
|
||||
@ -19,48 +17,49 @@ public class Dijkshtra {
|
||||
int m = in.nextInt();
|
||||
|
||||
// Adjacency Matrix
|
||||
long w[][] = new long [n+1][n+1];
|
||||
long[][] w = new long[n + 1][n + 1];
|
||||
|
||||
//Initializing Matrix with Certain Maximum Value for path b/w any two vertices
|
||||
// Initializing Matrix with Certain Maximum Value for path b/w any two vertices
|
||||
for (long[] row : w) {
|
||||
Arrays.fill(row, 1000000l);
|
||||
Arrays.fill(row, 1000000L);
|
||||
}
|
||||
|
||||
/* From above,we Have assumed that,initially path b/w any two Pair of vertices is Infinite such that Infinite = 1000000l
|
||||
For simplicity , We can also take path Value = Long.MAX_VALUE , but i have taken Max Value = 1000000l */
|
||||
|
||||
// Taking Input as Edge Location b/w a pair of vertices
|
||||
for(int i = 0; i < m; i++) {
|
||||
int x = in.nextInt(),y=in.nextInt();
|
||||
for (int i = 0; i < m; i++) {
|
||||
int x = in.nextInt(), y = in.nextInt();
|
||||
long cmp = in.nextLong();
|
||||
|
||||
//Comparing previous edge value with current value - Cycle Case
|
||||
if(w[x][y] > cmp) {
|
||||
w[x][y] = cmp; w[y][x] = cmp;
|
||||
// Comparing previous edge value with current value - Cycle Case
|
||||
if (w[x][y] > cmp) {
|
||||
w[x][y] = cmp;
|
||||
w[y][x] = cmp;
|
||||
}
|
||||
}
|
||||
|
||||
// Implementing Dijkshtra's Algorithm
|
||||
Stack<Integer> t = new Stack<Integer>();
|
||||
Stack<Integer> t = new Stack<>();
|
||||
int src = in.nextInt();
|
||||
|
||||
for(int i = 1; i <= n; i++) {
|
||||
if(i != src) {
|
||||
for (int i = 1; i <= n; i++) {
|
||||
if (i != src) {
|
||||
t.push(i);
|
||||
}
|
||||
}
|
||||
|
||||
Stack <Integer> p = new Stack<Integer>();
|
||||
Stack<Integer> p = new Stack<>();
|
||||
p.push(src);
|
||||
w[src][src] = 0;
|
||||
|
||||
while(!t.isEmpty()) {
|
||||
while (!t.isEmpty()) {
|
||||
int min = 989997979;
|
||||
int loc = -1;
|
||||
|
||||
for(int i = 0; i < t.size(); i++) {
|
||||
for (int i = 0; i < t.size(); i++) {
|
||||
w[src][t.elementAt(i)] = Math.min(w[src][t.elementAt(i)], w[src][p.peek()] + w[p.peek()][t.elementAt(i)]);
|
||||
if(w[src][t.elementAt(i)] <= min) {
|
||||
if (w[src][t.elementAt(i)] <= min) {
|
||||
min = (int) w[src][t.elementAt(i)];
|
||||
loc = i;
|
||||
}
|
||||
@ -70,12 +69,12 @@ public class Dijkshtra {
|
||||
}
|
||||
|
||||
// Printing shortest path from the given source src
|
||||
for(int i = 1; i <= n; i++) {
|
||||
if(i != src && w[src][i] != 1000000l) {
|
||||
for (int i = 1; i <= n; i++) {
|
||||
if (i != src && w[src][i] != 1000000L) {
|
||||
System.out.print(w[src][i] + " ");
|
||||
}
|
||||
// Printing -1 if there is no path b/w given pair of edges
|
||||
else if(i != src) {
|
||||
else if (i != src) {
|
||||
System.out.print("-1" + " ");
|
||||
}
|
||||
}
|
||||
|
@ -5,19 +5,22 @@ package Others;
|
||||
* Dijkstra's algorithm,is a graph search algorithm that solves the single-source
|
||||
* shortest path problem for a graph with nonnegative edge path costs, producing
|
||||
* a shortest path tree.
|
||||
*
|
||||
* <p>
|
||||
* NOTE: The inputs to Dijkstra's algorithm are a directed and weighted graph consisting
|
||||
* of 2 or more nodes, generally represented by an adjacency matrix or list, and a start node.
|
||||
*
|
||||
* <p>
|
||||
* Original source of code: https://rosettacode.org/wiki/Dijkstra%27s_algorithm#Java
|
||||
* Also most of the comments are from RosettaCode.
|
||||
*
|
||||
*/
|
||||
//import java.io.*;
|
||||
|
||||
import java.util.*;
|
||||
|
||||
public class Dijkstra {
|
||||
private static final Graph.Edge[] GRAPH = {
|
||||
new Graph.Edge("a", "b", 7), //Distance from node "a" to node "b" is 7. In the current Graph there is no way to move the other way (e,g, from "b" to "a"), a new edge would be needed for that
|
||||
// Distance from node "a" to node "b" is 7.
|
||||
// In the current Graph there is no way to move the other way (e,g, from "b" to "a"),
|
||||
// a new edge would be needed for that
|
||||
new Graph.Edge("a", "b", 7),
|
||||
new Graph.Edge("a", "c", 9),
|
||||
new Graph.Edge("a", "f", 14),
|
||||
new Graph.Edge("b", "c", 10),
|
||||
@ -43,12 +46,14 @@ public class Dijkstra {
|
||||
}
|
||||
|
||||
class Graph {
|
||||
private final Map<String, Vertex> graph; // mapping of vertex names to Vertex objects, built from a set of Edges
|
||||
// mapping of vertex names to Vertex objects, built from a set of Edges
|
||||
private final Map<String, Vertex> graph;
|
||||
|
||||
/** One edge of the graph (only used by Graph constructor) */
|
||||
public static class Edge {
|
||||
public final String v1, v2;
|
||||
public final int dist;
|
||||
|
||||
public Edge(String v1, String v2, int dist) {
|
||||
this.v1 = v1;
|
||||
this.v2 = v2;
|
||||
@ -59,7 +64,8 @@ class Graph {
|
||||
/** One vertex of the graph, complete with mappings to neighbouring vertices */
|
||||
public static class Vertex implements Comparable<Vertex> {
|
||||
public final String name;
|
||||
public int dist = Integer.MAX_VALUE; // MAX_VALUE assumed to be infinity
|
||||
// MAX_VALUE assumed to be infinity
|
||||
public int dist = Integer.MAX_VALUE;
|
||||
public Vertex previous = null;
|
||||
public final Map<Vertex, Integer> neighbours = new HashMap<>();
|
||||
|
||||
@ -70,11 +76,9 @@ class Graph {
|
||||
private void printPath() {
|
||||
if (this == this.previous) {
|
||||
System.out.printf("%s", this.name);
|
||||
}
|
||||
else if (this.previous == null) {
|
||||
} else if (this.previous == null) {
|
||||
System.out.printf("%s(unreached)", this.name);
|
||||
}
|
||||
else {
|
||||
} else {
|
||||
this.previous.printPath();
|
||||
System.out.printf(" -> %s(%d)", this.name, this.dist);
|
||||
}
|
||||
@ -87,25 +91,26 @@ class Graph {
|
||||
return Integer.compare(dist, other.dist);
|
||||
}
|
||||
|
||||
@Override public String toString() {
|
||||
@Override
|
||||
public String toString() {
|
||||
return "(" + name + ", " + dist + ")";
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/** Builds a graph from a set of edges */
|
||||
public Graph(Edge[] edges) {
|
||||
graph = new HashMap<>(edges.length);
|
||||
|
||||
//one pass to find all vertices
|
||||
// one pass to find all vertices
|
||||
for (Edge e : edges) {
|
||||
if (!graph.containsKey(e.v1)) graph.put(e.v1, new Vertex(e.v1));
|
||||
if (!graph.containsKey(e.v2)) graph.put(e.v2, new Vertex(e.v2));
|
||||
}
|
||||
|
||||
//another pass to set neighbouring vertices
|
||||
// another pass to set neighbouring vertices
|
||||
for (Edge e : edges) {
|
||||
graph.get(e.v1).neighbours.put(graph.get(e.v2), e.dist);
|
||||
//graph.get(e.v2).neighbours.put(graph.get(e.v1), e.dist); // also do this for an undirected graph
|
||||
// graph.get(e.v2).neighbours.put(graph.get(e.v1), e.dist); // also do this for an undirected graph
|
||||
}
|
||||
}
|
||||
|
||||
@ -132,13 +137,14 @@ class Graph {
|
||||
private void dijkstra(final NavigableSet<Vertex> q) {
|
||||
Vertex u, v;
|
||||
while (!q.isEmpty()) {
|
||||
// vertex with shortest distance (first iteration will return source)
|
||||
u = q.pollFirst();
|
||||
if (u.dist == Integer.MAX_VALUE)
|
||||
break; // we can ignore u (and any other remaining vertices) since they are unreachable
|
||||
|
||||
u = q.pollFirst(); // vertex with shortest distance (first iteration will return source)
|
||||
if (u.dist == Integer.MAX_VALUE) break; // we can ignore u (and any other remaining vertices) since they are unreachable
|
||||
|
||||
//look at distances to each neighbour
|
||||
// look at distances to each neighbour
|
||||
for (Map.Entry<Vertex, Integer> a : u.neighbours.entrySet()) {
|
||||
v = a.getKey(); //the neighbour in this iteration
|
||||
v = a.getKey(); // the neighbour in this iteration
|
||||
|
||||
final int alternateDist = u.dist + a.getValue();
|
||||
if (alternateDist < v.dist) { // shorter path to neighbour found
|
||||
@ -161,6 +167,7 @@ class Graph {
|
||||
graph.get(endName).printPath();
|
||||
System.out.println();
|
||||
}
|
||||
|
||||
/** Prints the path from the source to every vertex (output order is not guaranteed) */
|
||||
public void printAllPaths() {
|
||||
for (Vertex v : graph.values()) {
|
||||
|
Loading…
Reference in New Issue
Block a user