84 lines
2.1 KiB
Java
84 lines
2.1 KiB
Java
/*
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@author : Mayank K Jha
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*/
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.Scanner;
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import java.util.Stack;
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public class Dijkshtra {
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public static void main(String[] args) throws IOException {
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Scanner in = new Scanner(System.in);
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// n = Number of nodes or vertices
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int n = in.nextInt();
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// m = Number of Edges
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int m = in.nextInt();
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// Adjacency Matrix
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long w[][] = new long [n+1][n+1];
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//Initializing Matrix with Certain Maximum Value for path b/w any two vertices
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for (long[] row : w) {
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Arrays.fill(row, 1000000l);
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}
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/* From above,we Have assumed that,initially path b/w any two Pair of vertices is Infinite such that Infinite = 1000000l
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For simplicity , We can also take path Value = Long.MAX_VALUE , but i have taken Max Value = 1000000l */
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// Taking Input as Edge Location b/w a pair of vertices
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for(int i = 0; i < m; i++) {
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int x = in.nextInt(),y=in.nextInt();
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long cmp = in.nextLong();
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//Comparing previous edge value with current value - Cycle Case
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if(w[x][y] > cmp) {
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w[x][y] = cmp; w[y][x] = cmp;
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}
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}
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// Implementing Dijkshtra's Algorithm
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Stack<Integer> t = new Stack<Integer>();
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int src = in.nextInt();
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for(int i = 1; i <= n; i++) {
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if(i != src) {
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t.push(i);
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}
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}
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Stack <Integer> p = new Stack<Integer>();
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p.push(src);
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w[src][src] = 0;
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while(!t.isEmpty()) {
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int min = 989997979;
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int loc = -1;
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for(int i = 0; i < t.size(); i++) {
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w[src][t.elementAt(i)] = Math.min(w[src][t.elementAt(i)], w[src][p.peek()] + w[p.peek()][t.elementAt(i)]);
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if(w[src][t.elementAt(i)] <= min) {
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min = (int) w[src][t.elementAt(i)];
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loc = i;
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}
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}
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p.push(t.elementAt(loc));
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t.removeElementAt(loc);
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}
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// Printing shortest path from the given source src
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for(int i = 1; i <= n; i++) {
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if(i != src && w[src][i] != 1000000l) {
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System.out.print(w[src][i] + " ");
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}
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// Printing -1 if there is no path b/w given pair of edges
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else if(i != src) {
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System.out.print("-1" + " ");
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}
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}
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}
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}
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