PAT-A1093

#include<stdio.h>#include<algorithm>#include<string.h>using namespace std;int main(){char c[100010];int i, len, nump[100010]={0},numt[100010]={0};long long  ans=0;scanf("%s",c);len=strlen(c);for(i=1;i<=len;i++){if(c[i-1]=='P')nump[i]=nump[i-1]+1;else nump[i]=nump[i-1];}for(i=len;i>0;i--){if(c[i-1]=='T')numt[i]=numt[i+1]+1;else numt[i]=numt[i+1];}for(i=1;i<=len;i++){if(c[i-1]=='A'){ans=(ans+nump[i]*numt[i])%1000000007;}}printf("%d\n",ans);return 0;}