docs：【0097-小明逛公园】补充 JAVA版本【基于三维数组的Floyd算法】

2025-07-14 06:55:41 +08:00 · 2024-12-12 16:53:50 +08:00
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--- a/problems/kamacoder/0097.小明逛公园.md
+++ b/problems/kamacoder/0097.小明逛公园.md
@ -424,6 +424,71 @@ floyd算法的时间复杂度相对较高，适合 稠密图且源点较多的

 ### Java 

+- 基于三维数组的Floyd算法
+
+```java
+public class FloydBase {
+
+    // public static int MAX_VAL = Integer.MAX_VALUE;
+    public static int MAX_VAL = 10005; // 边的最大距离是10^4(不选用Integer.MAX_VALUE是为了避免相加导致数值溢出)
+
+    public static void main(String[] args) {
+        // 输入控制
+        Scanner sc = new Scanner(System.in);
+        System.out.println("1.输入N M");
+        int n = sc.nextInt();
+        int m = sc.nextInt();
+
+        System.out.println("2.输入M条边");
+
+        // ① dp定义（grid[i][j][k] 节点i到节点j 可能经过节点K（k∈[1,n]））的最短路径
+        int[][][] grid = new int[n + 1][n + 1][n + 1];
+        for (int i = 1; i <= n; i++) {
+            for (int j = 1; j <= n; j++) {
+                for (int k = 0; k <= n; k++) {
+                    grid[i][j][k] = grid[j][i][k] = MAX_VAL; // 其余设置为最大值
+                }
+            }
+        }
+
+        // ② dp 推导：grid[i][j][k] = min{grid[i][k][k-1] + grid[k][j][k-1], grid[i][j][k-1]}
+        while (m-- > 0) {
+            int u = sc.nextInt();
+            int v = sc.nextInt();
+            int weight = sc.nextInt();
+            grid[u][v][0] = grid[v][u][0] = weight; // 初始化（处理k=0的情况） ③ dp初始化
+        }
+
+        // ④ dp推导：floyd 推导
+        for (int k = 1; k <= n; k++) {
+            for (int i = 1; i <= n; i++) {
+                for (int j = 1; j <= n; j++) {
+                    grid[i][j][k] = Math.min(grid[i][k][k - 1] + grid[k][j][k - 1], grid[i][j][k - 1]);
+                }
+            }
+        }
+
+        System.out.println("3.输入[起点-终点]计划个数");
+        int x = sc.nextInt();
+
+        System.out.println("4.输入每个起点src 终点dst");
+
+        while (x-- > 0) {
+            int src = sc.nextInt();
+            int dst = sc.nextInt();
+            // 根据floyd推导结果输出计划路径的最小距离
+            if (grid[src][dst][n] == MAX_VAL) {
+                System.out.println("-1");
+            } else {
+                System.out.println(grid[src][dst][n]);
+            }
+        }
+    }
+}
+```
+
+
+
 ### Python

 基于三维数组的Floyd