[LeetCode]Copy List with Random Pointer &Clone Graph 复杂链表的复制&图的复制

/**
 * Definition for singly-linked list with a random pointer.
 * struct RandomListNode {
 *     int label;
 *     RandomListNode *next, *random;
 *     RandomListNode(int x) : label(x), next(NULL), random(NULL) {}
 * };
 */
class Solution {//为了可以高速定位某个节点，採用确定性映射的方式，将复制链表的节点作为原链表相应节点的下一个节点
public:
    RandomListNode *copyRandomList(RandomListNode *head) {
        //每一个节点指向其复制链表相应的节点，从而可以高速定位该节点
        if(!head)return NULL;
        RandomListNode *p,*q;
        p=head;
        while(p){
            q=new RandomListNode(p->label);
            q->next=p->next;
            p->next=q;
            p=q->next;
        }
        p=head;
        while(p){
            q=p->next;
            if(p->random)
                q->random=p->random->next;
            p=q->next;
        }
        p=head;
        RandomListNode*head2=p->next;
        q=head2;
        while(p){
            p->next=q->next;
            p=p->next;
            if(p){
                q->next=p->next;
                q=q->next;
            }
        }
        return head2;
    }
};

Clone Graph

：

类似的，对于图的复制，必须找到一种能够对新图中节点进行映射，能高速定位新节点的地址，从而使新节点指向新节点。这里採用map映射。考虑到图节点的label可能反复（本题不反复），而节点地址不反复，所以以新旧节点为键值对。

/**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    map<UndirectedGraphNode*,UndirectedGraphNode*>mp;
    map<UndirectedGraphNode*,UndirectedGraphNode*>::iterator bg;
    UndirectedGraphNode* dfs(UndirectedGraphNode*p){
        if(!p)return NULL;
        if((bg=mp.find(p))!=mp.end())
            return bg->second;
        UndirectedGraphNode *q;
        mp[p]=q=new UndirectedGraphNode(p->label);
        for(int i=0,m=p->neighbors.size();i<m;++i){
            q->neighbors.push_back(dfs(p->neighbors[i]));
        }
        return q;
    }
    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        if(!node)return NULL;
        dfs(node);
        return mp[node];
    }
};