用java写一个计算树直径的代码

好的，以下是用Java写一个计算树直径的代码：

import java.util.*;

public class TreeDiameter {
    static int maxDiameter = 0;
    static int farthestNode = 0;
    static boolean[] visited;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<List<Integer>> graph = new ArrayList<>();
        for (int i = 0; i <= n; i++) {
            graph.add(new ArrayList<>());
        }
        for (int i = 1; i < n; i++) {
            int u = sc.nextInt();
            int v = sc.nextInt();
            graph.get(u).add(v);
            graph.get(v).add(u);
        }
        visited = new boolean[n + 1];
        dfs(graph, 1, 0);
        visited = new boolean[n + 1];
        dfs(graph, farthestNode, 0);
        System.out.println(maxDiameter);
    }

    static void dfs(List<List<Integer>> graph, int node, int depth) {
        visited[node] = true;
        if (depth > maxDiameter) {
            maxDiameter = depth;
            farthestNode = node;
        }
        for (int neighbor : graph.get(node)) {
            if (!visited[neighbor]) {
                dfs(graph, neighbor, depth + 1);
            }
        }
    }
}

希望能够帮到你！