stack을 이용해 같은게 옆에있으면 같이 빼버린다. def repeat_str(s): init = len(s) stack = [] cnt = 0 while s: pre = s.pop() if stack: if pre == stack[-1]: stack.pop() cnt += 1 else: stack.append(pre) else: stack.append(pre) return init - 2*cnt for test in range(1,int(input())+1): s = list(input()) print(f'#{test} {repeat_str(s)}')