【LeetCode】Clone Graph

參考鏈接

http://blog.csdn.net/doc_sgl/article/details/12995765

http://blog.csdn.net/sunbaigui/article/details/16843647 簡化版廣度優先遍歷

http://www.2cto.com/kf/201311/260615.html 深度優先遍歷

題目描述

Clone Graph

 

Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.

OJ's undirected graph serialization:

Nodes are labeled uniquely.

We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.

As an example, consider the serialized graph {0,1,2#1,2#2,2}.

The graph has a total of three nodes, and therefore contains three parts as separated by #.

1. First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
2. Second node is labeled as 1. Connect node 1 to node 2.
3. Third node is labeled as 2. Connect node 2 to node 2 (itself), thus forming a self-cycle.

Visually, the graph looks like the following:

       1
      / \
     /   \
    0 --- 2
         / \
         \_/

題目分析

關鍵點，一個原圖到克隆圖的map

總結

代碼示例

/**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        if(node == NULL) return NULL;
        map<UndirectedGraphNode *, UndirectedGraphNode *> hasCopied;
        queue<UndirectedGraphNode *> uncompleteCopied;
        hasCopied[node] = new UndirectedGraphNode(node->label);
        //hasCopied[NULL] = NULL;
        uncompleteCopied.push(node);
        while(!uncompleteCopied.empty())
        {
            UndirectedGraphNode* pCurNode = uncompleteCopied.front();
            uncompleteCopied.pop();
            for(int i = 0; i < pCurNode->neighbors.size(); ++i)
            {
                UndirectedGraphNode* pNeighborNode = pCurNode->neighbors[i];
                if(hasCopied.find(pNeighborNode) != hasCopied.end())
                    hasCopied[pCurNode]->neighbors.push_back(hasCopied[pNeighborNode]);
                else
                {
                    hasCopied[pNeighborNode] = new UndirectedGraphNode(pNeighborNode->label);
                    hasCopied[pCurNode]->neighbors.push_back(hasCopied[pNeighborNode]);
                    uncompleteCopied.push(pNeighborNode);
                }
            }
            
        }
        return hasCopied[node];
    }
};

推薦學習C++的資料

C++標準函數庫

http://download.csdn.net/detail/chinasnowwolf/7108919

在線C++API查詢

http://www.cplusplus.com/

map使用方法

http://www.cplusplus.com/reference/map/map/

queue使用方法

http://www.cplusplus.com/reference/queue/queue/

vector使用方法

http://www.cplusplus.com/reference/vector/vector/