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stackWithQueues.py
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executable file
·77 lines (68 loc) · 1.76 KB
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#!/usr/bin/python
#
#
class Stack:
#initialize your data structure here.
def __init__(self):
self.queue1 = []
self.queue2 = []
#@param x, an integer
#@return nothing
def push(self,x):
if not self.queue1:
self.queue2.append(x)
else:
self.queue1.append(x)
#@return nothing
def pop(self):
size = 0
if not self.queue1:
#queue1 is empty, shift queue2 to queue1, remove the last from queue2
tmp = 0
size = len(self.queue2)
while tmp < size - 1:
self.queue1.append(self.queue2.pop(0))
tmp = tmp + 1
self.queue2.pop(0)
else:
#queue2 is empty, shift queue1 to queue2, remove the last from queue1
tmp = 0
size = len(self.queue1)
while tmp < size - 1:
self.queue2.append(self.queue1.pop(0))
tmp = tmp + 1
self.queue1.pop(0)
#@return an integer
def top(self):
result = 0
size = 0
if not self.queue1:
#queue1 is empty, shift queue2 to queue1, remove the last from queue2
tmp = 0
size = len(self.queue2)
while tmp < size - 1:
self.queue1.append(self.queue2[0])
self.queue2.pop(0)
tmp = tmp + 1
result = self.queue2[0]
self.queue2.pop(0)
self.queue1.append(result)
else:
#queue2 is empty, shift queue1 to queue2, remove the last from queue1
tmp = 0
size = len(self.queue1)
while tmp < size -1:
self.queue2.append(self.queue1[0])
self.queue1.pop(0)
tmp = tmp + 1
result = self.queue[0]
self.queue1.pop(0)
self.queue2.append(result)
return result
#@return an boolean
def empty(self):
return len(self.queue1) == 0 and len(self.queue2) == 0
def main():
print "hello"
if __name__ == "__main__":
main()