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【链表】单向链表的反转

Posted on Edited on In

三指针法遍历，一次遍历则完成反转：

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ListNode* ReverseList(ListNode* pHead) {
     //no node
     if(pHead==nullptr) return pHead;
     ListNode* pre=nullptr,*mid=pHead,*last=nullptr;
     //more node/single node
     while(mid->next!=nullptr){
         //confirm the location
         last=mid->next;
         mid->next=pre; pre=mid;mid=last; 
     }
     mid->next=pre;
     pHead=mid;
     return pHead;
 }