Implement queue using stacks lcci
(leetcode.cc)[https://leetcode-cn.com/problems/implement-queue-using-stacks-lcci/submissions/]
class MyQueue: # FIFO
def __init__(self):
self.stack_in = []
self.stack_out = []
def push(self, x: int) -> None:
self.stack_in.append(x)
def pop(self) -> int:
if len(self.stack_out)==0:
for i in range(len(self.stack_in)):
self.stack_out.append(self.stack_in.pop())
return self.stack_out.pop()
def peek(self) -> int:
if len(self.stack_out)==0:
for i in range(len(self.stack_in)):
self.stack_out.append(self.stack_in.pop())
temp = self.stack_out.pop()
self.stack_out.append(temp)
return temp
def empty(self) -> bool:
return len(self.stack_in)==0 and len(self.stack_out)==0
# Your MyQueue object will be instantiated and called as such:
# obj = MyQueue()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.peek()
# param_4 = obj.empty()