Added Linear Search, changed Binary search

-Linear Search was added.
-Made Both searches final and static ( There is no reason to have to instantiate them). Also Changed the tests to include the new static methods.
-Added a new test, searching an empty array.
This commit is contained in:
Panagiotis Karapas 2018-10-31 18:21:04 +00:00 committed by GitHub
parent 08dc6adfcc
commit c6ce36b19b
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4 changed files with 76 additions and 14 deletions

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@ -8,7 +8,7 @@ package src.main.java.com.search;
* Average performance O(log n)
* Worst-case space complexity O(1)
*/
public class BinarySearch {
public final class BinarySearch{
/**
* @param array is an array where the element should be found
@ -16,18 +16,18 @@ public class BinarySearch {
* @param <T> is any comparable type
* @return index of the element
*/
public <T extends Comparable<T>> int findIndex(T array[], T key) {
public static <T extends Comparable<T>> int findIndex(T array[], T key) {
return search(array, key, 0, array.length-1);
}
/**
* @param array The array to make the binary search
* @param key The number you are looking for
* @param array The array to search
* @param key The element you are looking for
* @param left The lower bound
* @param right The upper bound
* @return the location of the key
**/
private <T extends Comparable<T>> int search(T array[], T key, int left, int right){
private static <T extends Comparable<T>> int search(T array[], T key, int left, int right){
if (left > right) {
return -1; // Key not found
}

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@ -0,0 +1,35 @@
package src.main.java.com.search;
/**
* Linear search is an algorithm which finds the position of a target value within an array (Usually unsorted)
*
* Worst-case performance O(n)
* Best-case performance O(1)
* Average performance O(n)
* Worst-case space complexity O(1)
*/
public final class LinearSearch {
/**
* @param array is an array where the element should be found
* @param key is an element which should be found
* @param <T> is any comparable type
* @return index of the element
*/
public static <T extends Comparable<T>> int findIndex(T array[], T key) {
return search(array, key);
}
/**
* @param array The array to search
* @param key The element you are looking for
* @return the location of the key or -1 if the element is not found
**/
private static <T extends Comparable<T>> int search(T array[], T key){
for(int i = 0; i < array.length;i++) {
if (array[i].compareTo(key) == 0){
return i;
}
}
return -1;
}
}

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@ -8,17 +8,18 @@ public class BinarySearchTest {
@Test
public void testBinarySearch() {
BinarySearch binarySearch = new BinarySearch();
Integer[] arr1 = {1,2,3,4,5};
Assert.assertEquals("Incorrect index", 2, binarySearch.findIndex(arr1,3));
Assert.assertEquals("Incorrect index", 0, binarySearch.findIndex(arr1,1));
Assert.assertEquals("Incorrect index", -1, binarySearch.findIndex(arr1,8));
Assert.assertEquals("Incorrect index", -1, binarySearch.findIndex(arr1,-2));
Assert.assertEquals("Incorrect index", 2, BinarySearch.findIndex(arr1,3));
Assert.assertEquals("Incorrect index", 0, BinarySearch.findIndex(arr1,1));
Assert.assertEquals("Incorrect index", -1, BinarySearch.findIndex(arr1,8));
Assert.assertEquals("Incorrect index", -1, BinarySearch.findIndex(arr1,-2));
String[] arr2 = {"A", "B", "C", "D"};
Assert.assertEquals("Incorrect index", 2, binarySearch.findIndex(arr2,"C"));
Assert.assertEquals("Incorrect index", 1, binarySearch.findIndex(arr2,"B"));
Assert.assertEquals("Incorrect index", -1, binarySearch.findIndex(arr2,"F"));
Assert.assertEquals("Incorrect index", 2, BinarySearch.findIndex(arr2,"C"));
Assert.assertEquals("Incorrect index", 1, BinarySearch.findIndex(arr2,"B"));
Assert.assertEquals("Incorrect index", -1, BinarySearch.findIndex(arr2,"F"));
String[] arr3 = {};
Assert.assertEquals("Incorrect index", -1, BinarySearch.findIndex(arr3, ""));
}
}

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@ -0,0 +1,26 @@
package src.test.java.com.search;
import org.junit.Assert;
import org.junit.Test;
import src.main.java.com.search.LinearSearch;
public class LinearSearchTest {
@Test
public void testLinearSearch() {
Integer[] arr1 = {1,2,3,4,5};
Assert.assertEquals("Incorrect index", 2, LinearSearch.findIndex(arr1,3));
Assert.assertEquals("Incorrect index", 0, LinearSearch.findIndex(arr1,1));
Assert.assertEquals("Incorrect index", -1, LinearSearch.findIndex(arr1,8));
Assert.assertEquals("Incorrect index", -1, LinearSearch.findIndex(arr1,-2));
String[] arr2 = {"A", "B", "C", "D"};
Assert.assertEquals("Incorrect index", 2, LinearSearch.findIndex(arr2,"C"));
Assert.assertEquals("Incorrect index", 1, LinearSearch.findIndex(arr2,"B"));
Assert.assertEquals("Incorrect index", -1, LinearSearch.findIndex(arr2,"F"));
String[] arr3 = {};
Assert.assertEquals("Incorrect index", -1, LinearSearch.findIndex(arr3, ""));
}
}