Leetcode 133. Clone Graph

最新推荐文章于 2022-03-06 18:27:32 发布

ruihuank

最新推荐文章于 2022-03-06 18:27:32 发布

阅读量182

点赞数

CC 4.0 BY-SA版权

分类专栏： leetcode 笔记文章标签： leetcode

本文链接：https://blog.youkuaiyun.com/ruihuank/article/details/79398269

leetcode 笔记专栏收录该内容

127 篇文章

订阅专栏

本文探讨了在图结构中使用深度优先搜索（DFS）与广度优先搜索（BFS）进行节点及其邻居的深拷贝实现。通过具体的C++代码示例展示了两种方法的具体实现细节。

DFS

/**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    using UMAP = unordered_map<UndirectedGraphNode*, UndirectedGraphNode*>;

    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        if (node  == nullptr) return nullptr;
        UMAP mp;
        return reSolver(node, mp);
    }

private:
    UndirectedGraphNode *reSolver(UndirectedGraphNode * node, UMAP& mp) {
        UndirectedGraphNode *ret = new UndirectedGraphNode(node->label);
        mp[node] = ret;

        for (auto p : node->neighbors) {
            auto it = mp.begin();
            if ((it = mp.find(p)) != mp.end())
                ret->neighbors.emplace_back(it->second); 
            else
                ret->neighbors.emplace_back(reSolver(p, mp)); 
        }
        return ret;

    }
};

BFS

/**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:

    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        if (node  == nullptr) return nullptr;

        UndirectedGraphNode* ret = new UndirectedGraphNode(node->label);
        using UMAP = unordered_map<UndirectedGraphNode*, UndirectedGraphNode*>;
        UMAP mp {make_pair(node, ret)};
        deque<UndirectedGraphNode*> dp;
        dp.emplace_back(node);

        while (!dp.empty()) {
            size_t n = dp.size();
            for (int i = 0; i != n; ++i) {
                auto pSrc = dp.front();
                dp.pop_front();
                auto pDst = mp[pSrc];
                for (auto p : pSrc->neighbors) {
                    auto it = cbegin(mp);
                    if ((it = mp.find(p)) != cend(mp))
                        pDst->neighbors.emplace_back(it->second);
                    else {
                        auto tmp = new UndirectedGraphNode(p->label);
                        mp[p] = tmp; 
                        pDst->neighbors.emplace_back(tmp);
                        dp.emplace_back(p);
                    }
                }
            }
        }

        return ret;
    }

};