leetcode/stack.py at master · thomastien/leetcode · GitHub

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'''
push(x) -- Push element x to the back of queue.
pop() -- Removes the element from in front of queue.
peek() -- Get the front element.
empty() -- Return whether the queue is empty.

'''


class Queue(object):
    def __init__(self):
        self.stack = []

    def push(self, x):
        self.stack += str(x)

    def pop(self):
        if len(self.stack) > 0:
            self.stack.pop(0)

    def peek(self):
        if len(self.stack) == 0:
            return None
        else:
            return int(self.stack[0])

    def empty(self):
        if len(self.stack) ==0:
            return True
        else:
            return False