232.用棧實現佇列
class MyQueue:
def __init__(self):
self.queue = []
self.size = 0
def push(self, x: int) -> None:
self.queue.append(x)
self.size += 1
def pop(self) -> int:
self.size -= 1
return self.queue.pop(0)
def peek(self) -> int:
if self.size != 0:
return self.queue[0]
else:
return None
def empty(self) -> bool:
if self.size == 0:
return True
else:
return False
225. 用佇列實現棧
class MyStack:
def __init__(self):
self.stack_in = []
self.stack_out = []
self.size = 0
def push(self, x: int) -> None:
if self.stack_out:
temp = self.stack_out.pop()
self.stack_in.append(temp)
self.stack_in.append(x)
self.size += 1
def pop(self) -> int:
if self.stack_out:
self.size -= 1
return self.stack_out.pop(-1)
elif self.stack_in:
self.size -= 1
return self.stack_in.pop(-1)
def top(self) -> int:
if self.stack_out:
return self.stack_out[-1]
else:
temp = self.stack_in.pop(-1)
self.stack_out.append(temp)
return temp
def empty(self) -> bool:
if self.size == 0:
return True
else:
return False