【leetcode】【189】Rotate Array

#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
	void rotate(vector<int>& nums, int k) { //可参考STL源码剖析rotate()算法
		k = k%nums.size(); 
		vector<int>::iterator first = nums.begin();
		vector<int>::iterator last = nums.end();
		vector<int>::iterator middle = last - k;
		//边界条件
		if (first == middle || middle == last)
			return;
		vector<int>::iterator i = middle;
		while (true){
			//前后段一一交换
			int temp = *i;
			*i = *first;
			*first = temp;
			++first;
			++i;
			//判断前段先结束还是后段先结束
			if (first == middle){
				if (i == last)//同时结束，整个就结束
					return;
				middle = i;
			}
			else if (i == last)
				i = middle;
		}
	}
};

int main(){
	vector<int> vec = { 1, 2 };
	Solution solution;
	solution.rotate(vec, 3);
	for (vector<int>::iterator it = vec.begin(); it != vec.end(); ++it)
		cout << *it << " ";
	cout << endl;

	system("pause");
	return 0;
}