4294 Problem A求n!(ni) [1*+]递归算法设计-递归分治672624295 Problem B斐波那契数列(递归)算法设计-递归分治671874162 Problem C数塔算法设计-动态规划竞赛-低年级组651474296 Problem D第k小整数算法设计-递归分治661054297 Problem E子网掩码算法设计-模拟66103