miku

2026-05-19 07:04:53 +05:30
parent 825e915f5f
commit 5beeb7c652
5 changed files with 254 additions and 0 deletions
@@ -0,0 +1,85 @@
+import java.util.*;
+public class bellmanFord{
+    static class Edge{
+        int src, dest, weigh;
+        Edge(int s, int d, int w){
+            src = s;
+            dest = d;
+            weigh = w;
+        }
+    }
+    static void printPath(int vertex, int[] parent){
+        if(vertex==-1) return;
+        printPath(parent[vertex], parent);
+        System.out.print(vertex+" ");
+
+    }
+    public static void main(String[] args){
+        Scanner sc = new Scanner(System.in);
+        System.out.print("Enter no. of vertices and edges: ");
+        int n = sc.nextInt();
+        int e = sc.nextInt();
+        int[] parent = new int[n];
+        Edge[] edges = new Edge[e];
+        int[] dist = new int[n];
+
+        System.out.print("Enter the edges(src dest weight): ");
+        for(int i=0;i<e;i++){
+            int s = sc.nextInt();
+            int d = sc.nextInt();
+            int w = sc.nextInt();
+            edges[i] = new Edge(s,d,w);
+            
+        }
+
+        System.out.println("\nEnter source vertex: ");
+        int s = sc.nextInt();
+
+        for(int i=0;i<n;i++){
+            dist[i] = 999;
+            parent[i] = -1;
+        }
+        dist[s] = 0;
+
+        for(int i=1;i<=n-1;i++){
+            for(int j=0;j<e;j++){
+                int sr = edges[j].src;
+                int d = edges[j].dest;
+                int w = edges[j].weigh;
+                if(dist[sr]!=999 && dist[sr] + w < dist[d]){
+                    dist[d] = dist[sr]+w;
+                    parent[d] = sr;
+                }
+
+
+            }
+        }
+        boolean negcycle = false;
+
+        for(int j=0;j<e;j++){
+                int sr = edges[j].src;
+                int d = edges[j].dest;
+                int w = edges[j].weigh;
+                if(dist[sr]!=999 && dist[sr] + w < dist[d]){
+                    dist[d] = dist[sr]+w;
+                    negcycle = true;
+                    break;
+                    
+                }
+        }
+        if(negcycle){
+            System.out.println("\nNegative cycle exists.");
+
+        }else{
+            System.out.println("\nShortest paths from source vertex " + s + ":\n");
+            for(int i=0;i<n;i++){
+                System.out.println("vertex: "+i);
+                System.out.println("Cost: "+ dist[i]);
+                System.out.println("Path: ");
+                printPath(i, parent);
+                System.out.println();
+            }
+        }
+        sc.close();
+    }
+}