更新0096.城市间货物运输III 基于Bellman_ford一般解法Java版本

problems/kamacoder/0096.城市间货物运输III.md

@@ -636,6 +636,71 @@ dijkstra 是贪心的思路 每一次搜索都只会找距离源点最近的非
 ## 其他语言版本
 
 ### Java 
+```Java
+import java.util.*;
+
+public class Main {
+    // 基于Bellman_for一般解法解决单源最短路径问题
+    // Define an inner class Edge
+    static class Edge {
+        int from;
+        int to;
+        int val;
+        public Edge(int from, int to, int val) {
+            this.from = from;
+            this.to = to;
+            this.val = val;
+        }
+    }
+
+    public static void main(String[] args) {
+        // Input processing
+        Scanner sc = new Scanner(System.in);
+        int n = sc.nextInt();
+        int m = sc.nextInt();
+
+        List<Edge> graph = new ArrayList<>();
+
+        for (int i = 0; i < m; i++) {
+            int from = sc.nextInt();
+            int to = sc.nextInt();
+            int val = sc.nextInt();
+            graph.add(new Edge(from, to, val));
+        }
+
+        int src = sc.nextInt();
+        int dst = sc.nextInt();
+        int k = sc.nextInt();
+
+        int[] minDist = new int[n + 1];
+        int[] minDistCopy;
+
+        Arrays.fill(minDist, Integer.MAX_VALUE);
+        minDist[src] = 0;
+
+        for (int i = 0; i < k + 1; i++) { // Relax all edges k + 1 times
+            minDistCopy = Arrays.copyOf(minDist, n + 1);
+            for (Edge edge : graph) {
+                int from = edge.from;
+                int to = edge.to;
+                int val = edge.val;
+                // Use minDistCopy to calculate minDist
+                if (minDistCopy[from] != Integer.MAX_VALUE && minDist[to] > minDistCopy[from] + val) {
+                    minDist[to] = minDistCopy[from] + val;
+                }
+            }
+        }
+        
+        // Output printing
+        if (minDist[dst] == Integer.MAX_VALUE) {
+            System.out.println("unreachable");
+        } else {
+            System.out.println(minDist[dst]);
+        }
+    }
+}
+
+```
 
 ### Python