#include "bits/stdc++.h"
#include "dna.h"
using namespace std;
string a,b;
vector<vector<int> > leta,letb;
// ac ca at ta ct tc
// 0 1 2 3 4 5
vector<vector<int> > cont;
int get_comb(char up, char down){
if(up=='A' && down=='C') return 0;
if(up=='C' && down=='A') return 1;
if(up=='A' && down=='T') return 2;
if(up=='T' && down=='A') return 3;
if(up=='C' && down=='T') return 4;
return 5;
}
int get_letter(char act){
if(act=='A') return 0;
if(act=='T') return 1;
return 2;
}
void init(std::string A, std::string B) {
a=A;
b=B;
int n=a.size();
leta.resize(n,vector<int> (3,0));
letb.resize(n,vector<int> (3,0));
cont.resize(n,vector<int> (6,0));
leta[0][get_letter(a[0])]++;
letb[0][get_letter(b[0])]++;
for(int i=1;i<n;i++){
for(int j=0;j<3;j++){
leta[i][j]=leta[i-1][j];
letb[i][j]=letb[i-1][j];
}
leta[i][get_letter(a[i])]++;
letb[i][get_letter(b[i])]++;
}
cont[0][get_comb(a[0],b[0])]++;
for(int i=1;i<n;i++){
for(int j=0;j<6;j++)
cont[i][j]=cont[i-1][j];
cont[i][get_comb(a[i],b[i])]++;
}
}
int count_letter(bool is_a, int i, int j, int pos){
if(is_a)
return (i==0) ? leta[j][pos] : leta[j][pos] - leta[i-1][pos];
return (i==0) ? letb[j][pos] : letb[j][pos] - letb[i-1][pos];
}
int count_comb(int i, int j, int pos){
return (i==0) ? cont[j][pos] : cont[j][pos] - cont[i-1][pos];
}
void count(int &res, int &f, int &s){
res+=f;
s-=f;
f=0;
}
int get_distance(int x, int y) {
for(int i=0;i<3;i++)
if(count_letter(1,x,y,i)!=count_letter(0,x,y,i)) return -1;
vector<int> v(6);
for(int i=0;i<6;i++)
v[i]=count_comb(x,y,i);
int res=0;
for(int i=0;i<6;i+=2)
(v[i]<v[i+1]) ? count(res,v[i],v[i+1]) : count(res,v[i],v[i+1]);
for(int i=0;i<4;i+=2)
res+=max(v[i],v[i+1]);
return res;
}
