CF1494A.ABC String

普及/提高-

通过率:0%

AC君温馨提醒

该题目为【codeforces】题库的题目,您提交的代码将被提交至codeforces进行远程评测,并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供,我们无法保证该服务的稳定性,若提交后无反应,请等待一段时间后再进行重试。

题目描述

You are given a string aa , consisting of nn characters, nn is even. For each ii from 11 to nn aia_i is one of 'A', 'B' or 'C'.

A bracket sequence is a string containing only characters "(" and ")". A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and "+" between the original characters of the sequence. For example, bracket sequences "()()" and "(())" are regular (the resulting expressions are: "(1)+(1)" and "((1+1)+1)"), and ")(", "(" and ")" are not.

You want to find a string bb that consists of nn characters such that:

  • bb is a regular bracket sequence;
  • if for some ii and jj ( 1i,jn1 \le i, j \le n ) ai=aja_i=a_j , then bi=bjb_i=b_j .

In other words, you want to replace all occurrences of 'A' with the same type of bracket, then all occurrences of 'B' with the same type of bracket and all occurrences of 'C' with the same type of bracket.

Your task is to determine if such a string bb exists.

输入格式

The first line contains a single integer tt ( 1t10001 \le t \le 1000 ) — the number of testcases.

Then the descriptions of tt testcases follow.

The only line of each testcase contains a string aa . aa consists only of uppercase letters 'A', 'B' and 'C'. Let nn be the length of aa . It is guaranteed that nn is even and 2n502 \le n \le 50 .

输出格式

For each testcase print "YES" if there exists such a string bb that:

  • bb is a regular bracket sequence;
  • if for some ii and jj ( 1i,jn1 \le i, j \le n ) ai=aja_i=a_j , then bi=bjb_i=b_j .

Otherwise, print "NO".

You may print every letter in any case you want (so, for example, the strings yEs, yes, Yes and YES are all recognized as positive answer).

输入输出样例

  • 输入#1

    4
    AABBAC
    CACA
    BBBBAC
    ABCA

    输出#1

    YES
    YES
    NO
    NO

说明/提示

In the first testcase one of the possible strings bb is "(())()".

In the second testcase one of the possible strings bb is "()()".

首页