[백준] 3986번 좋은단어 - 파이썬

https://www.acmicpc.net/problem/3986

3986번: 좋은 단어

 

[코드]

import sys

input = sys.stdin.readline
N = int(input())
words = []
[words.append(input().rstrip()) for _ in range(N)]

answer = 0

for word in words:
    stack = []
    for char in word:
        if stack:
            if stack[-1] == 'A':
                if char == 'A':
                    stack.pop()
                else:  # 'B'
                    stack.append(char)
            else:  # 'B'
                if char == 'B':
                    stack.pop()
                else:  # 'A'
                    stack.append(char)
        else:
            stack.append(char)
    if not stack:
        answer += 1

print(answer)