#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
string aa, bb;
int n = 100010;
vector< vector<int> >pref(10, vector<int>(n, 0));
void init(std::string a, std::string b) {
aa=" "+a;
bb=" "+b;
n = a.length();
/*
0 uk
1 AT
2 TA
3 AC
4 CA
5 TC
6 CT
TAC
CTA
*/
a = " " + a;
b = " " + b;
for(int i = 0; i<=6; i++)
{
pref[i][0]=0;
for(int j = 1; j<=n; j++)
{
pref[i][j]=pref[i][j-1];
if(i==0 && a[j]!=b[j])pref[i][j]++;
else if(i==1 && a[j]=='A' && b[j]=='T')pref[i][j]++;
else if(i==2 && a[j]=='T' && b[j]=='A')pref[i][j]++;
else if(i==3 && a[j]=='A' && b[j]=='C')pref[i][j]++;
else if(i==4 && a[j]=='C' && b[j]=='A')pref[i][j]++;
else if(i==5 && a[j]=='T' && b[j]=='C')pref[i][j]++;
else if(i==6 && a[j]=='C' && b[j]=='T')pref[i][j]++;
}
}
}
int get_distance(int x, int y)
{
x++;
y++;
map<char, int>m1, m2;
for(int i = x; i<=y; i++)
{
m1[aa[i]]++;
m2[bb[i]]++;
}
if(m1['A']!=m2['A'] || m1['T']!=m2['T'] || m1['C']!=m2['C'])
{
return -1;
}
int cnt = 0;
cnt += min(pref[1][y]-pref[1][x-1], pref[2][y]-pref[2][x-1]);
//cout<<cnt<<"\n";
cnt += min(pref[3][y]-pref[3][x-1], pref[4][y]-pref[4][x-1]);
//cout<<cnt<<"\n";
cnt+= min(pref[5][y]-pref[5][x-1], pref[6][y]-pref[6][x-1]);
int uk = pref[0][y]-pref[0][x-1];
int ans = cnt + 2*(uk - 2*cnt)/3;
//
return ans;
}
