CodeforcesRound#247(Div.2)ABC:Codeforces Round #247 (Div. 2) http://codeforces.com/contest/431 代码均已投放：https://github.com/illuz/WayToACM/tree/master/CodeForces/431 A - Black Square 题目地址 题意 ： Jury玩别踩白块，游戏中有四个