华为OD机试 - 查找一个有向网络的头节点和尾节点（Java & JS & Python & C & C++）

在有向图中，头节点是入度为0的节点，尾节点是出度为0的节点。

以下是针对不同编程语言的解决方案：

1. Java:

import java.util.*;
 
public class Solution {
    /**
     * 获取头节点和尾节点
     * @param graph 图的邻接表表示
     * @return 头节点和尾节点数组
     */
    public int[] getHeadAndTailNodes(List<List<Integer>> graph) {
        int[] degrees = new int[graph.size()];
        boolean[] isHead = new boolean[graph.size()];
        boolean[] isTail = new boolean[graph.size()];
        
        // 计算每个节点的度
        for (int i = 0; i < graph.size(); i++) {
            for (int neighbor : graph.get(i)) {
                degrees[neighbor]++;
            }
        }
        
        // 标记头节点和尾节点
        for (int i = 0; i < graph.size(); i++) {
            if (degrees[i] == 0) {
                isHead[i] = true;
            }
            if (graph.get(i).isEmpty()) {
                isTail[i] = true;
            }
        }
        
        // 统计头节点和尾节点的数量
        int headCount = 0, tailCount = 0;
        for (int i = 0; i < isHead.length; i++) {
            if (isHead[i]) {
                headCount++;
            }
            if (isTail[i]) {
                tailCount++;
            }
        }
        
        // 不存在头节点或尾节点的情况
        if (headCount == 0 || tailCount == 0) {
            return new int[]{-1, -1};
        }
        
        // 寻找唯一的头节点和尾节点
        int headNode = -1, tailNode = -1;
        for (int i = 0; i < isHead.length; i++) {
            if (isHead[i]) {
                if (headNode == -1) {
                    headNode = i;
                } else {
                    headNode = -1; // 不唯一
                    break;
                }
            }
            if (isTail[i]) {
                if (tailNode == -1) {
                    tailNode = i;
                } else {
                    tailNode = -1; // 不唯一
                    break;
                }
            }
        }
        
        return new int[]{headNode, tailNode};
    }
}

2. JavaScript:

/**
 * @param {number[][]} graph
 * @return {number[]}
 */
var getHeadAndTailNodes = function(graph) {
    let degrees = new Array(graph.length).fill(0);
    let isHead = new Array(graph.length).fill(false);
    let isTail = new Array(graph.length).fill(false);
    
    // 计算每个节点的度
    for (let i = 0; i < graph.length; i++) {
        for (let neighbor of graph[i]) {
            degrees[neighbor]++;
        }
    }
    
    //