[BOJ] 10828. 스택

www.acmicpc.net/problem/10828

10828번: 스택

풀이

• 경우에 맞게 구현

n = int(input())
stack = []
ans = []
for _ in range(n):
    input_order = input().split(' ')
    if input_order[0] == 'push':
        stack.insert(0, input_order[1])
    elif input_order[0] == 'pop':
        if len(stack):
            ans.append(stack.pop(0))
        else:
            ans.append(-1)
    elif input_order[0] == 'size':
        ans.append(len(stack))
    elif input_order[0] == 'empty':
        if len(stack):
            ans.append(0)
        else:
            ans.append(1)
    elif input_order[0] == 'top':
        if len(stack):
            ans.append(stack[0])
        else:
            ans.append(-1)

for a in ans:
    print(a)