55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
// Source : https://oj.leetcode.com/problems/remove-nth-node-from-end-of-list/
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// Author : Hao Chen
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// Date : 2014-06-21
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/**********************************************************************************
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*
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* Given a linked list, remove the nth node from the end of list and return its head.
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*
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* For example,
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*
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* Given linked list: 1->2->3->4->5, and n = 2.
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*
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* After removing the second node from the end, the linked list becomes 1->2->3->5.
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*
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* Note:
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* Given n will always be valid.
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* Try to do this in one pass.
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*
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*
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**********************************************************************************/
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/**
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* Definition for singly-linked list.
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* struct ListNode {
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* int val;
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* ListNode *next;
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* ListNode(int x) : val(x), next(NULL) {}
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* };
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*/
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class Solution {
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public:
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ListNode *removeNthFromEnd(ListNode *head, int n) {
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if (head==NULL || n<=0){
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return NULL;
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}
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ListNode fakeHead(0);
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fakeHead.next=head;
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head=&fakeHead;
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ListNode *p1, *p2;
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p1=p2=head;
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for(int i=0; i<n; i++){
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if (p2==NULL) return NULL;
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p2=p2->next;
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}
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while (p2->next!=NULL){
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p2=p2->next;
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p1=p1->next;
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}
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p1->next = p1->next->next;
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return head->next;
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}
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};
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