无向图中到环的距离

/*
题目思路:
1. 使用BFS来寻找图中的环。首先，通过DFS找出所有的环中的节点。
2. 然后，通过BFS计算每个节点到最近环节点的距离。
3. 返回一个包含所有节点到最近环节点距离的数组。
*/
import java.util.*;
import java.util.stream.*;

class Solution {
    public int[] distanceToCycle(int n, int[][] edges) {
        List<List<Integer>> graph = IntStream.range(0, n)
                                              .mapToObj(i -> new ArrayList<Integer>())
                                              .collect(Collectors.toList());
        for (int[] edge : edges) {
            graph.get(edge[0]).add(edge[1]);
            graph.get(edge[1]).add(edge[0]);
        }

        boolean[] visited = new boolean[n];
        int[] parent = IntStream.generate(() -> -1).limit(n).toArray();
        int[] cycleNodes = IntStream.generate(() -> -1).limit(n).toArray();

        Deque<Integer> queue = new ArrayDeque<>();
        findCycle(0, -1, visited, parent, graph, cycleNodes, queue);

        int[] distances = IntStream.generate(() -> Integer.MAX_VALUE).limit(n).toArray();
        queue.forEach(node -> distances[node] = 0);

        while (!queue.isEmpty()) {
            int node = queue.poll();
            for (int neighbor : graph.get(node)) {
                if (distances[neighbor] == Integer.MAX_VALUE) {
                    distances[neighbor] = distances[node] + 1;
                    queue.offer(neighbor);
                }
            }
        }

        return distances;
    }

    private boolean findCycle(int node, int parent, boolean[] visited, int[] parents, List<List<Integer>> graph, int[] cycleNodes, Deque<Integer> queue) {
        visited[node] = true;
        parents[node] = parent;

        for (int neighbor : graph.get(node)) {
            if (neighbor == parent) continue;
            if (visited[neighbor]) {
                int cur = node;
                while (cur != neighbor) {
                    cycleNodes[cur] = 0;
                    queue.offer(cur);
                    cur = parents[cur];
                }
                cycleNodes[neighbor] = 0;
                queue.offer(neighbor);
                return true;
            }
            if (findCycle(neighbor, node, visited, parents, graph, cycleNodes, queue)) {
                return true;
            }
        }
        return false;
    }
}