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 };

 C#

 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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