ACM--字符串--Two Substrings--水

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#ACM #字符串 #Two Substrings #水

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本文探讨了一个字符串问题，即判断给定的字符串是否包含两个非重叠的子串“AB”和“BA”。通过使用strstr()函数进行查找，并确保两个子串不发生重叠。

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题目地址：传送门

D - Two Substrings

Time Limit:2000MS Memory Limit:262144KB 64bit IO Format:%I64d & %I64u

Submit Status

Description

You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order).

Input

The only line of input contains a string s of length between 1 and 10⁵ consisting of uppercase Latin letters.

Output

Print "YES" (without the quotes), if string s contains two non-overlapping substrings "AB" and "BA", and "NO" otherwise.

Sample Input

Input

ABA

Output

NO

Input

BACFAB

Output

YES

Input

AXBYBXA

Output

NO

Hint

In the first sample test, despite the fact that there are substrings "AB" and "BA", their occurrences overlap, so the answer is "NO".

In the second sample test there are the following occurrences of the substrings: BACFAB.

In the third sample test there is no substring "AB" nor substring "BA".

题解：这里可以使用strstr()函数，需要<string.h>头文件

#include<iostream>
#include<stdio.h>
#include<string.h>
using namespace std;
char s[100001];
int main(){
   char *c;
   scanf("%s",&s);
   if((c=strstr(s,"AB"))!=NULL&&strstr(c+2,"BA")!=NULL){
        printf("YES\n");
        return 0;
   }
   if((c=strstr(s,"BA"))!=NULL&&strstr(c+2,"AB")!=NULL){
        printf("YES\n");
        return 0;
   }
   printf("NO\n");
}