[알고리즘] 스택(Stack) 백준 10828번 - 스택

num = int(input())

array = []
result = []

for _ in range(num):
    inputValue = input()
    request = inputValue.split()[0]

    if request == 'push':
        array.append(int(inputValue.split()[1]))
    elif request == 'top':
        if len(array) == 0:
            result.append(-1)
        else:
            result.append(array[len(array)-1])
    elif request == 'size':
        result.append(len(array))
    elif request == 'empty':
        if len(array) == 0:
            result.append(1)
        else:
            result.append(0)
    elif request == 'pop':
        if len(array) == 0:
            result.append(-1)
        else:
            popValue = array.pop()
            result.append(popValue)

for i in result:
    print(i)