【leetcode】【单链表】【61】Merge k Sorted Lists

#include<iostream>
using namespace std;

struct ListNode {
	int val;
	ListNode *next;
	ListNode(int x) : val(x), next(NULL) {}
};

class Solution {
public:
	ListNode* rotateRight(ListNode* head, int k) {
		if (head == NULL||head->next == NULL)
			return head;

		int numOfNodes=0;
		ListNode* cur = head;
		ListNode* last = head;
		while (cur){//找出链表长度
			++numOfNodes;
			last = cur;
			cur = cur->next;
		}
		k = k%numOfNodes;
		if (k == 0) //注意，开始没有考虑到，要右旋转长度为0
			return head;

		ListNode* preCur = head;
		cur = head;
		k = numOfNodes - k;
		while (k--){
			preCur = cur;
			cur = cur->next;
		}
		preCur->next = NULL;
		last->next = head;
		head = cur;
		return head;
	}
	ListNode* createList(ListNode* head){
		int numOfNode;
		int value;
		cout << "please input number of listNode:";
		cin >> numOfNode;
		cin >> value;
		head = new ListNode(value);
		ListNode* cur = head;
		for (int i = 1; i < numOfNode; ++i){
			cin >> value;
			ListNode* temp = new ListNode(value);
			cur->next = temp;
			cur = temp;
		}
		return head;
	}
	void printNode(ListNode* head){
		ListNode* cur = head;
		while (cur){
			cout << cur->val << " ";
			cur = cur->next;
		}
		cout << endl;
	}
};

int main(){
	ListNode* head = NULL;
	Solution lst;
	head = lst.createList(head);
	lst.printNode(head);

	head = lst.rotateRight(head, 0);
	lst.printNode(head);

	system("pause");
	return 0;
}