1#
大 中
小 發表於 2014-1-18 09:24 PM (第 3768 天)
顯示全部帖子
think of a stack is a container, push is put thing into it, pop is take out thing from it.
take (A) as example
sequence -- stack -- output (when pop)
push 1 -- |1|X|X|X|X|X| -- n/a
push 2 -- |1|2|X|X|X|X| -- \ /
push 3 -- |1|2|3|X|X|X| -- \ /
pop -- |1|2|X|X|X|X| -- 3
pop -- |1|X|X|X|X|X| -- 3,2
pop -- |X|X|X|X|X|X| -- 3,2,1
push 4 -- |4|X|X|X|X|X| -- \ /
pop -- |X|X|X|X|X|X| -- 3,2,1,4
push 5 -- |5|X|X|X|X|X| -- \ /
pop -- |X|X|X|X|X|X| -- 3,2,1,4,5
push 6 -- |6|X|X|X|X|X| -- \ /
pop -- |X|X|X|X|X|X| -- 3,2,1,4,5,6
to understand it , try it on (C) and (D) as your self exercises ,
finally try your best on (B) as it is impossible to have a sequence .
[ 本帖最後由 tony625 於 2014-1-18 09:29 PM 編輯 ]
