题解 | List -> Stack

Python的list既可以作为stack，也可以作为queue

# Total number of operations
n = int(input())

# List can be used as a stack
stack = []

while n:
    # [operation [number]]
    field = input().split()

    # push == append
    if field[0] == 'push':
        stack.append(field[1])
    
    # peek == last item
    elif field[0] == 'top':
        print(stack[-1]) if stack else print('error')
    
    # pop == pop
    else:
        print(stack.pop()) if stack else print('error')
    
    # Next oeration
    n -= 1