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。

 1 /**
 2  * Definition for undirected graph.
 3  * struct UndirectedGraphNode {
 4  *     int label;
 5  *     vector<UndirectedGraphNode *> neighbors;
 6  *     UndirectedGraphNode(int x) : label(x) {};
 7  * };
 8  */
 9 class Solution {
10 public:
11     UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
12         // IMPORTANT: Please reset any member data you declared, as
13         // the same Solution instance will be reused for each test case.
14         if (node == NULL) return NULL;
15         map<UndirectedGraphNode*, UndirectedGraphNode*> S;
16         UndirectedGraphNode *res = new UndirectedGraphNode(node->label);
17         S[node] = res;
18         queue<UndirectedGraphNode *> que;
19         que.push(node);
20         while (!que.empty()) {
21             UndirectedGraphNode *t = que.front();
22             que.pop();
23             for (int i = 0; i < t->neighbors.size(); i++) {
24                 UndirectedGraphNode *nei = t->neighbors[i];
25                 if (S.count(nei)) S[t]->neighbors.push_back(S[nei]);
26                 else {
27                     que.push(nei);
28                     UndirectedGraphNode *tmp = new UndirectedGraphNode(nei->label);
29                     S[nei] = tmp;
30                     S[t]->neighbors.push_back(tmp);
31                 }
32             }
33         }
34         return res;
35     }
36 };

 1 /**
 2  * Definition for undirected graph.
 3  * public class UndirectedGraphNode {
 4  *     public int label;
 5  *     public IList<UndirectedGraphNode> neighbors;
 6  *     public UndirectedGraphNode(int x) { label = x; neighbors = new List<UndirectedGraphNode>(); }
 7  * };
 8  */
 9 public class Solution {
10     public UndirectedGraphNode CloneGraph(UndirectedGraphNode node) {
11         if (node == null) return null;
12         Dictionary<UndirectedGraphNode, UndirectedGraphNode> S = new Dictionary<UndirectedGraphNode, UndirectedGraphNode>();
13         UndirectedGraphNode ans = new UndirectedGraphNode(node.label);
14         S.Add(node, ans);
15         Queue<UndirectedGraphNode> que = new Queue<UndirectedGraphNode>();
16         que.Enqueue(node);
17         while (que.Count != 0) {
18             UndirectedGraphNode peek = que.Peek();
19             que.Dequeue();
20             for (int i = 0; i < peek.neighbors.Count; i++) {
21                 UndirectedGraphNode nei = peek.neighbors[i];
22                 if (S.ContainsKey(nei)) S[peek].neighbors.Add(S[nei]);
23                 else {
24                     que.Enqueue(nei);
25                     UndirectedGraphNode tmp = new UndirectedGraphNode(nei.label);
26                     S.Add(nei, tmp);
27                     S[peek].neighbors.Add(tmp);
28                 }
29             }
30         }
31         return ans;
32     }
33 }

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