java实现一个最小生成树算法

import java.util.Arrays;

//最小生成树（Minimum Spanning Tree，MST）是一个图论中的概念，它是一个连通图中生成树中边权值之和最小的树
public class Test_33 {

    private static final int INF = Integer.MAX_VALUE;

    public void prim(int[][] graph) {
        int n = graph.length;
        int[] parent = new int[n]; // 存储最小生成树的父节点
        int[] key = new int[n]; // 存储到每个节点的最小权值
        boolean[] mstSet = new boolean[n];

        Arrays.fill(key, INF);
        key[0] = 0; // 设置第一个节点的权值为0
        parent[0] = -1;

        for (int i = 0; i < n - 1; i++) {
            int u = minKey(key, mstSet);
            mstSet[u] = true;

            for (int v = 0; v < n; v++) {
                if (graph[u][v] != 0 && !mstSet[v] && graph[u][v] < key[v]) {
                    parent[v] = u;
                    key[v] = graph[u][v];
                }
            }
        }

        System.out.println("Edge \tWeight");
        for (int i = 1; i < n; i++) {
            System.out.println(parent[i] + " - " + i + "\t" + graph[i][parent[i]]);
        }
    }

    private int minKey(int[] key, boolean[] mstSet) {
        int min = INF;
        int minIndex = -1;

        for (int i = 0; i < key.length; i++) {
            if (!mstSet[i] && key[i] < min) {
                min = key[i];
                minIndex = i;
            }
        }

        return minIndex;
    }

    public static void main(String[] args) {
        int[][] graph = {
                {0, 2, 0, 6, 0},
                {2, 0, 3, 8, 5},
                {0, 3, 0, 0, 7},
                {6, 8, 0, 0, 9},
                {0, 5, 7, 9, 0}
        };

        Test_33 primMST = new Test_33();
        primMST.prim(graph);
    }

}