摘要：
Pop Sequence Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. You are supposed to tell 阅读全文
摘要：
List Leaves Given a tree, you are supposed to list all the leaves in the order of top down, and left to right. Input Specification: Each input file co 阅读全文