4294 Problem A求n!(ni) [1*+]递归算法设计-递归分治1393654295 Problem B斐波那契数列(递归)算法设计-递归分治1372974162 Problem C数塔算法设计-动态规划竞赛-低年级组1352524296 Problem D第k小整数ACM1352044297 Problem E子网掩码算法设计-模拟133168