Day1
NOIP2012 Kings game: Swap adjacent elements to see whether it will get better solution to greedy ideas to find the optimal solution.
USACO12FEB
CF 1214C: the right elements in the right will not get more than the right to get the right parenthesis excellent leftmost
CF 1157C: linear sweep around a
CF 1175D: seeking a prefix and the entire array is then selected n-1 preceding the largest among the k-1 is subtracted, the minimum value is obtained.
CF 1213F：