劍指offer--鏈表中倒數第k個結點

輸入一個鏈表，輸出該鏈表中倒數第k個結點。

思路：快慢指針

#include <iostream>
#include<vector>
using namespace std;
/* 創建一個單鏈表 */
struct ListNode{
    int val;
    ListNode* next;
};
void createList(ListNode* pHead){
    ListNode* p = pHead;
	cout<<"節點的個數：";
	int num;
	cin>>num;
    for (int i = 1; i <= num; ++i) {
        ListNode* pNewNode = new ListNode;
        pNewNode->val = i; // 將新節點的值賦值爲i
        pNewNode->next = NULL;
        p->next = pNewNode; // 上一個節點指向這個新建立的節點
        p = pNewNode; // p節點指向這個新的節點
    }
}
int main(){
        ListNode* head = NULL;
	head = new ListNode;

	createList(head);

	ListNode *p1,*p2;
	p1 = head;
	p2 = head;
	cout<<"倒數第k個節點，k = ";
	int k;
	cin>>k;

	for(int i=0;i<k-1;i++){
		if(p1->next != NULL){
			p1 = p1->next;
		}
		else 
			break;
	}
	while(p1->next!=NULL){
		p1 = p1->next;
		p2 = p2->next;
	}
	cout<<"倒數第k個節點的值："<<p2->val<<endl;

	return 0;
}