CodeForces 550A Two Substrings 简单题

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A. Two Substrings
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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.

Examples
input
ABA
output
NO
input
BACFAB
output
YES
input
AXBYBXA
output
NO
Note

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".

拿一个简单题来当做我的第一篇博客吧,就这样,代码都是自己写的,所有有的可能不是最佳的(๑•̀ㅂ•́)و✧

#include <bits/stdc++.h>using namespace std;int main(){    string a;    int len,p,q,k;    while(cin>>a)    {        len=a.size();        k=p=q=0;        for(int i=0;i<len;i++)        {            if(a[i]=='A')            {                if(i+2<len&&a[i+1]=='B'&&a[i+2]=='A')                {                    k++;                    i+=2;                }                else if(i+1<len&&a[i+1]=='B')                {                    p=1;                    i++;                }            }            if(a[i]=='B')            {                if(i+2<len&&a[i+1]=='A'&&a[i+2]=='B')                {                    k++;                    i+=2;                }                else if(i+1<len&&a[i+1]=='A')                {                    q=1;                    i++;                }            }        }        if(p+q+k>=2)            cout<<"YES"<<endl;        else            cout<<"NO"<<endl;    }    return 0;}

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