LeetCode: Clone Graph

这题的思路就是建一个old graph到新的graph点的对应map，queue表示还未访问过的old graph的点的队列，如果queue的front的点的neighbors vector里有未访问的点就添加到队列里。

/**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if (node == NULL) return NULL;
        map<UndirectedGraphNode*, UndirectedGraphNode*> S;
        UndirectedGraphNode *res = new UndirectedGraphNode(node->label);
        S[node] = res;
        queue<UndirectedGraphNode *> que;
        que.push(node);
        while (!que.empty()) {
            UndirectedGraphNode *t = que.front();
            que.pop();
            for (int i = 0; i < t->neighbors.size(); i++) {
                UndirectedGraphNode *nei = t->neighbors[i];
                if (S.count(nei)) S[t]->neighbors.push_back(S[nei]);
                else {
                    que.push(nei);
                    UndirectedGraphNode *tmp = new UndirectedGraphNode(nei->label);
                    S[nei] = tmp;
                    S[t]->neighbors.push_back(tmp);
                }
            }
        }
        return res;
    }
};

 C#

/**
 * Definition for undirected graph.
 * public class UndirectedGraphNode {
 *     public int label;
 *     public IList<UndirectedGraphNode> neighbors;
 *     public UndirectedGraphNode(int x) { label = x; neighbors = new List<UndirectedGraphNode>(); }
 * };
 */
public class Solution {
    public UndirectedGraphNode CloneGraph(UndirectedGraphNode node) {
        if (node == null) return null;
        Dictionary<UndirectedGraphNode, UndirectedGraphNode> S = new Dictionary<UndirectedGraphNode, UndirectedGraphNode>();
        UndirectedGraphNode ans = new UndirectedGraphNode(node.label);
        S.Add(node, ans);
        Queue<UndirectedGraphNode> que = new Queue<UndirectedGraphNode>();
        que.Enqueue(node);
        while (que.Count != 0) {
            UndirectedGraphNode peek = que.Peek();
            que.Dequeue();
            for (int i = 0; i < peek.neighbors.Count; i++) {
                UndirectedGraphNode nei = peek.neighbors[i];
                if (S.ContainsKey(nei)) S[peek].neighbors.Add(S[nei]);
                else {
                    que.Enqueue(nei);
                    UndirectedGraphNode tmp = new UndirectedGraphNode(nei.label);
                    S.Add(nei, tmp);
                    S[peek].neighbors.Add(tmp);
                }
            }
        }
        return ans;
    }
}