非降路径与栈的计数

栈计数是指序列１，２，…，ｎ，按不同的顺序进、出栈所得到的不同的排列的个数。在［１］和［２］中用不同的方法间接给出了栈计数的值。本文用非降路径与栈操作序列的对应关系，给出了栈计数的一种新的解法，它较之［１］和［２］方法更为直观、简洁。

Non一descending Paths and Stack Output Countiug

Stack output counting refers to the nuinber ofdiffcrent stack output permu-tations according to the orders of stack pushing and poping operations for an input se-quence 1,2,…n The number was obtained as a secondhand result in[1]8nd[2].In this paper,we give a new method to solve the problem by using a mapping between non一descendingpaths and stack operationslhe method is more direct and simpler than that of[1]and[2]。