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Merge pull request #696 from GHumorBS/patch-1

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Update 0232.用栈实现队列.md
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程序员Carl
2021-09-02 08:51:09 +08:00
committed by GitHub
parent aefaa02b67 55753bb558
commit d6b72d135b
1 changed files with 8 additions and 15 deletions
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problems/0232.用栈实现队列.md
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@ -205,33 +205,26 @@ class MyQueue:
def pop(self) -> int: def pop(self) -> int:
""" """
1. 检查如果out里面元素，则直接pop Removes the element from in front of queue and returns that element.
2. 如果out没有元素，就把in里面的元素（除了第一个）依次pop后装进out里面
3. 直接把in剩下的元素pop出来，就是queue头部的
""" """
if self.empty: if self.empty():
return None return None
if self.stack_out: if self.stack_out:
return self.stack_out.pop() return self.stack_out.pop()
else: else:
for i in range(1, len(self.stack_in)): for i in range(len(self.stack_in)):
self.stack_out.append(self.stack_in.pop()) self.stack_out.append(self.stack_in.pop())
return self.stack_in.pop() return self.stack_out.pop()
def peek(self) -> int: def peek(self) -> int:
""" """
1. 查out有没有元素，有就把最上面的返回 Get the front element.
2. 如果out没有元素，就把in最下面的返回
""" """
if self.empty: ans = self.pop()
return None self.stack_out.append(ans)
return ans
if self.stack_out:
return self.stack_out[-1]
else:
return self.stack_in[0]
def empty(self) -> bool: def empty(self) -> bool: