1093. Count PAT's (25)

1093. Count PAT’s (25)

#include<stdio.h>#include<string.h>#define N 100005int main(){    long long count=0;    int i=0,k=0,p=0,t=0,b[N],a[N],n;    char s[N],ch;    while((ch=getchar())!='\n')    {        if(ch=='P')p++;        if(ch=='A')a[k++]=p;        s[i++]=ch;    }    s[i]='\0';    n=k;    for(i=strlen(s)-1;i>=0;i--)    {        if(s[i]=='T')t++;        if(s[i]=='A')b[--k]=t;    }    for(i=0;i<n;i++)    {        count+=a[i]*b[i];        count%=1000000007;    }    printf("%lld",count);}