#include "dna.h"
#include "bits/stdc++.h"
using namespace std;
string A,B;
int pa[3][100001];
int pb[3][100001];
void init(string a,string b)
{
A=a;
B=b;
int n=a.size();
pa[0][0]=(a[0]=='A');
pa[1][0]=(a[0]=='C');
pa[2][0]=(a[0]=='T');
for(int i=1;i<n;i++)
{
pa[0][i]=pa[0][i-1]+(a[i]=='A');
pa[1][i]=pa[1][i-1]+(a[i]=='C');
pa[2][i]=pa[2][i-1]+(a[i]=='T');
}
pb[0][0]=(b[0]=='A');
pb[1][0]=(b[0]=='C');
pb[2][0]=(b[0]=='T');
for(int i=1;i<n;i++)
{
pb[0][i]=pb[0][i-1]+(b[i]=='A');
pb[1][i]=pb[1][i-1]+(b[i]=='C');
pb[2][i]=pb[2][i-1]+(b[i]=='T');
}
}
int get(int l,int r,int x,int t){
if(t==0){
if(l==0) return pa[x][r];
else return pa[x][r]-pa[x][l-1];
}
else{
if(l==0) return pb[x][r];
else return pb[x][r]-pb[x][l-1];
}
}
int get_distance(int x,int y)
{
vector<int>ca(3),cb(3);
ca[0]=get(x,y,0,0);
ca[1]=get(x,y,1,0);
ca[2]=get(x,y,2,0);
cb[0]=get(x,y,0,1);
cb[1]=get(x,y,1,1);
cb[2]=get(x,y,2,1);
for(int i=0;i<3;i++) if(ca[i]!=cb[i]) return -1;
int AC=0;
int CA=0;
int AT=0;
int TA=0;
int CT=0;
int TC=0;
for(int i=x;i<=y;i++){
if(A[i]==B[i]) continue;
if(B[i]=='A'&&A[i]=='C') AC++;
if(B[i]=='C'&&A[i]=='A') CA++;
if(B[i]=='A'&&A[i]=='T') AT++;
if(B[i]=='T'&&A[i]=='A') TA++;
if(B[i]=='C'&&A[i]=='T') CT++;
if(B[i]=='T'&&A[i]=='C') TC++;
}
int res=0;
int s1=min(AC,CA);
int s2=min(AT,TA);
int s3=min(CT,TC);
res+=s1;
res+=s2;
res+=s3;
AC-=s1;
CA-=s1;
AT-=s2;
TA-=s2;
CT-=s3;
TC-=s3;
int add=(AC+CA+AT+TA+CT+TC);
return (res+((add/3)*2));
}
