题目1单选题
若让元素1,2,3,4,5依次进栈,则出栈次序不可能出现在( )种情况A. 5,4,3,2,1B. 2,1,5,4,3C. 4,3,1,2,5D. 2,3,5,4,1
题目3单选题
已知一个栈的进栈序列是ABC,出栈序列为CBA,经过的栈操作是( )A. push,pop,push,pop,push,popB. push,push,push,pop,pop,popC. push,push,pop,pop,push,popD. push,pop,push,push,pop,pop