題目
用兩個棧來實現一個隊列,完成隊列的Push和Pop操作。 隊列中的元素爲int類型。
解答
兩個棧來回倒就能訪問棧底了,沒啥說的
# -*- coding:utf-8 -*-
class Solution:
def __init__(self):
self.stark1 = [] # 用list模擬棧 在後續代碼中不得違反棧的操作規則
self.stark2 = [] # 即只能對其 append 或 pop
def push(self, node):
# 搬移元素
for _ in range(len(self.stark2)):
self.stark1.append(self.stark2.pop())
# 插入元素
self.stark1.append(node)
def pop(self):
# 搬移元素
for _ in range(len(self.stark1)):
self.stark2.append(self.stark1.pop())
# 彈出元素
return self.stark2.pop()
s = Solution()
# ["PSH1","PSH2","PSH3","POP","POP","PSH4","POP","PSH5","POP","POP"]
s.push(1)
s.push(2)
s.push(3)
print(s.pop())
print(s.pop())
s.push(4)
print(s.pop())
s.push(5)
print(s.pop())
print(s.pop())
# 對應輸出應該爲: 1,2,3,4,5