#include "dna.h"
#include<bits/stdc++.h>
using namespace std;
const int n=100000;
int AT[n]{0},TA[n]{0},AC[n]{0},CA[n]{0},TC[n]{0},CT[n]{0};
void init(string a, string b) {
for(int i=0;i<n;i++){
if(i!=0){
AT[i]=AT[i-1];TA[i]=TA[i-1];AC[i]=AC[i-1];CA[i]=CA[i-1];TC[i]=TC[i-1];CT[i]=CT[i-1];
}
if(a[i]=='A'&&b[i]=='T')AT[i]++;
else if(a[i]=='T'&&b[i]=='A')TA[i]++;
else if(a[i]=='A'&&b[i]=='C')AC[i]++;
else if(a[i]=='C'&&b[i]=='A')CA[i]++;
else if(a[i]=='T'&&b[i]=='C')TC[i]++;
else if(a[i]=='C'&&b[i]=='T')CT[i]++;
}
}
int get_distance(int x, int y) {
int ans=0;
x=max(x-1,0);
ans+=min(TA[y]-TA[x],AT[y]-AT[x])+min(AC[y]-AC[x],CA[y]-CA[x])+min(TC[y]-TC[x],CT[y]-CT[x]);
int rem=abs(TA[y]-TA[x]-(AT[y]-AT[x]))+abs(AC[y]-AC[x]-(CA[y]-CA[x]))+abs(TC[y]-TC[x]-(CT[y]-CT[x]));
if(rem%3!=0)return -1;
ans+=rem/3*2;
return ans;
}
