#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
string aa, bb;
int n = 100010;
vector<vector<int>> pref(7, vector<int>(n, 0)), cnt1(3, vector<int>(n, 0)), cnt2(3, 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
*/
a = " " + a;
b = " " + b;
for (int i = 0; i <= 6; i++) {
for (int j = 1; j <= n; j++) {
cnt1[0][j] = cnt1[0][j - 1];
cnt1[1][j] = cnt1[1][j - 1];
cnt1[2][j] = cnt1[2][j - 1];
cnt2[0][j] = cnt2[0][j - 1];
cnt2[1][j] = cnt2[1][j - 1];
cnt2[2][j] = cnt2[2][j - 1];
if (a[j] == 'A') cnt1[0][j]++;
else if (a[j] == 'T') cnt1[1][j]++;
else cnt1[2][j]++;
if (b[j] == 'A') cnt2[0][j]++;
else if (b[j] == 'T') cnt2[1][j]++;
else cnt2[2][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++;
if (cnt1[0][y] - cnt1[0][x - 1] != cnt2[0][y] - cnt2[0][x - 1] ||
cnt1[1][y] - cnt1[1][x - 1] != cnt2[1][y] - cnt2[1][x - 1] ||
cnt1[2][y] - cnt1[2][x - 1] != cnt2[2][y] - cnt2[2][x - 1]) {
return -1;
}
int cnt = 0;
cnt += min(pref[1][y] - pref[1][x - 1], pref[2][y] - pref[2][x - 1]);
cnt += min(pref[3][y] - pref[3][x - 1], pref[4][y] - pref[4][x - 1]);
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;
//cout<<cnt<<" "<<uk<<"\n";
//cout<<pref[0][y]<<" "<<pref[0][x-1]<<"\n";
return ans;
}
