#include "dna.h"
#include<bits/stdc++.h>
using namespace std;
int Aa[200000];
int Ta[200000];
int Ca[200000];
int Ab[200000];
int Tb[200000];
int Cb[200000];
int cc[200000];
void init(std::string a, std::string b) {
int n = a.size();
for(int i=0;i<n;i++){
Aa[i+1] = Aa[i] + (a[i]=='A');
Ta[i+1] = Ta[i] + (a[i]=='T');
Ca[i+1] = Ca[i] + (a[i]=='C');
Ab[i+1] = Ab[i] + (b[i]=='A');
Tb[i+1] = Tb[i] + (b[i]=='T');
Cb[i+1] = Cb[i] + (b[i]=='C');
cc[i+1] = cc[i] + (a[i]==b[i]);
//cout<<Aa[i+1]<<" "<<Ta[i+1]<<" "<<Ca[i+1]<<" "<<cc[i+1]<<endl;
}
}
int get_distance(int x, int y) {
x++, y++;
int cnt = y-x+1;
if(Aa[y]-Aa[x-1] != Ab[y]-Ab[x-1]) return -1;
if(Ta[y]-Ta[x-1] != Tb[y]-Tb[x-1]) return -1;
if(Ca[y]-Ca[x-1] != Cb[y]-Cb[x-1]) return -1;
return (cnt - (cc[y]-cc[x-1]) + 1)/2;
}
