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  • leetcode Remove Nth Node From End of List

    题目连接

    https://leetcode.com/problems/remove-nth-node-from-end-of-list/

    Remove Nth Node From End of List

    Description

    Given a linked list, remove the $n^{th}$ node from the end of list and return its head.

    For example,

    Given linked list: 1->2->3->4->5, and n = 2.

    After removing the second node from the end, the linked list becomes 1->2->3->5.
    Note:
    Given n will always be valid.
    Try to do this in one pass.

    /**
     * Definition for singly-linked list.
     * struct ListNode {
     *     int val;
     *     ListNode *next;
     *     ListNode(int x) : val(x), next(NULL) {}
     * };
     */
    class Solution {
    public:
    	ListNode* removeNthFromEnd(ListNode* head, int n) {
    		tot = 0;
    		if (!head) return head;
    		ListNode *p = head;
    		for (; p; p = p->next) tot++;
    		if (n > tot) return head;
    		p = head;
    		int cur = 1;
    		if (tot == n) {
    			head = head->next;
    			delete p;
    		} else {
    			while (p) {
    				if (cur++ == tot - n) break;
    				p = p->next;
    			}
    			ListNode *ret = p->next;
    			p->next = ret ? ret->next : NULL;
    			delete ret;
    		}
    		return head;
    	}
    private:
    	int tot;
    };
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  • 原文地址:https://www.cnblogs.com/GadyPu/p/5040233.html
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