969. Pancake Sorting

O(n²) time O(1) space
因为题目要求任何解法都可以，所以用最直白的思路，先从大到小找到每一个数，然后把这个数翻转到最开始，再翻转到对应的位置即可
类似bubble sort

class Solution {
public:
    vector<int> pancakeSort(vector<int>& A) {
        int n = A.size();
        vector<int> res;
        for (int i = n - 1; i >= 0; --i) {
            int k = distance(begin(A), find(begin(A), begin(A) + i + 1, i + 1));
            res.push_back(k + 1);
            reverse(begin(A), begin(A) + k + 1);
            res.push_back(i + 1);
            reverse(begin(A), begin(A) + i + 1);
        }
        return res;
    }
};