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 if a given sequence of numbers is a possible pop sequence of the stack. for example, if m is 5 and n is 7, we can obtain 1, 2, 3, 4, 5, 6, 7 from the stack, but not 3, 2, 1, 7, 5, 6, 4.

这个题目描述了一个场景：给定一个最多可以容纳m个数的栈，按1，2，3，……，n的顺序压入n个数，并随机弹出。你需要判断给定的数字序列是否可能是该栈的弹出序列。例如，当m为5，n为7时，我们可以从栈中获得1，2，3，4，5，6，7，但不能获取3，2，1，7，5，6，4。