class Solution {public:	void nextPermutation(vector
    
      &num) {		int n = num.size();		if (n == 1)return;		for (int i = n - 2, ii = n - 1; i >= 0; i--, ii--)		if (num[i] < num[ii])		{			int j = n - 1;			while (num[j] <= num[i])j--;//从尾部找到第一个比num[i]大的数，一定可以找到			swap(num[i], num[j]);			reverse(num.begin() + ii, num.end());			return;		}		reverse(num.begin(), num.end());	}};