拓扑排序代码java

以下是一个使用Java实现拓扑排序的示例代码：

import java.util.*;

public class TopologicalSort {
    private int V; // 顶点的数量
    private List<List<Integer>> adj; // 邻接表

    public TopologicalSort(int v) {
        V = v;
        adj = new ArrayList<>(v);
        for (int i = 0; i < v; ++i)
            adj.add(new ArrayList<>());
    }

    public void addEdge(int v, int w) {
        adj.get(v).add(w);
    }

    public void topologicalSort() {
        int[] inDegree = new int[V]; // 记录每个顶点的入度

        // 计算每个顶点的入度
        for (int v = 0; v < V; ++v) {
            List<Integer> neighbors = adj.get(v);
            for (int neighbor : neighbors) {
                inDegree[neighbor]++;
            }
        }

        Queue<Integer> queue = new LinkedList<>();
        for (int v = 0; v < V; ++v) {
            if (inDegree[v] == 0) {
                queue.add(v);
            }
        }

        List<Integer> result = new ArrayList<>();
        while (!queue.isEmpty()) {
            int v = queue.poll();
            result.add(v);

            List<Integer> neighbors = adj.get(v);
            for (int neighbor : neighbors) {
                inDegree[neighbor]--;
                if (inDegree[neighbor] == 0) {
                    queue.add(neighbor);
                }
            }
        }

        // 输出拓扑排序结果
        for (int v : result) {
            System.out.print(v + " ");
        }
    }

    public static void main(String[] args) {
        TopologicalSort g = new TopologicalSort(6);
        g.addEdge(5, 2);
        g.addEdge(5, 0);
        g.addEdge(4, 0);
        g.addEdge(4, 1);
        g.addEdge(2, 3);
        g.addEdge(3, 1);

        System.out.println("拓扑排序结果：");
        g.topologicalSort();
    }
}