83 lines
2.3 KiB
Java
83 lines
2.3 KiB
Java
import java.util.*;
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public class floydWarshall{
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static void print(int u, int v, int[][]next){
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if(next[u][v]==-1){
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System.out.println("no path exists");
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return;
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}
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System.out.print(u);
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while(u!=v){
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u = next[u][v];
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System.out.print("->"+u);
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}
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System.out.println();
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}
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public static void main(String[] args){
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Scanner sc = new Scanner(System.in);
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System.out.print("\nEnter number of vertices: ");
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int n = sc.nextInt();
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int[][] graph = new int[n][n];
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System.out.println("Enter distance matrix: ");
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for(int i =0;i<n;i++){
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for(int j =0;j<n;j++){
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graph[i][j] = sc.nextInt();
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}
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}
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int[][] next = new int[n][n];
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int[][] dist = new int[n][n];
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for(int i = 0;i<n;i++){
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for(int j =0;j<n;j++){
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dist[i][j] = graph[i][j];
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if(graph[i][j]!=999 && i!=j)
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next[i][j] = j;
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else
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next[i][j] = -1;
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}
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}
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for(int k =0;k<n;k++){
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for(int i=0;i<n;i++){
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for(int j=0;j<n;j++){
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if(dist[i][k]!=999 && dist[k][j]!= 999 && dist[i][k]+dist[k][j]< dist[i][j]){
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dist[i][j] = dist[i][k] + dist[k][j];
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next[i][j] = next[i][k];
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}
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}
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}
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}
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boolean negativeCycle = false;
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for(int i=0;i<n;i++){
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if(dist[i][i]<0){
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negativeCycle = true;
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break;
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}
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}
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if(negativeCycle){
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System.out.println("Negative cycle exists");
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}else{
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System.out.println("No negative cycle");
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}
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System.out.println("Shortest path matrix");
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for(int i=0;i<n;i++){
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for(int j=0;j<n;j++){
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System.out.print(dist[i][j]+ " ");
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}
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System.out.println();
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}
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System.out.print("\nEnter source vertex: ");
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int u = sc.nextInt();
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System.out.print("\nENter dest vertex: ");
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int v = sc.nextInt();
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System.out.print("\nShortes path: ");
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print(u,v,next);
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System.out.println("Cost: "+ dist[u][v]);
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sc.close();
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}
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}
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