[백준] 스택

https://www.acmicpc.net/problem/10828

10828번: 스택

 

스택은 Last In First Out!

 

import sys

N = int(sys.stdin.readline())
stack = []

for i in range(N):
    cmd = sys.stdin.readline().strip().split()
    
    if cmd[0] == 'push':
        stack.append(cmd[1])
    
    elif cmd[0] == 'pop':
        print(-1 if not stack else stack.pop())
    
    elif cmd[0] == 'size':
        print(len(stack))
    
    elif cmd[0] == 'empty':
        print(0 if stack else 1)
    
    else:
        print(-1 if not stack else stack[-1])