#include "dna.h"
#include <bits/stdc++.h>
#define ll long long int
using namespace std;
string a, b; int n;
vector<ll> as[3], bs[3];
// [0] = A, [1] = T, [2] = C
int get_distance(int x, int y) {
for (int i = 0; i < 3; i++) {
ll suma = as[i][y], sumb = bs[i][y];
if (x > 0) {
suma -= as[i][x-1];
sumb -= bs[i][x-1];
}
if (suma != sumb) return -1;
}
int cnt = 0;
for (int i = x; i <= y; i++) {
if (a[i] != b[i]) cnt++;
}
return cnt/2;
}
// int main() {
// string aa, bb; cin >> aa >> bb;
void init(string aa, string bb) {
a = aa; b = bb; n = a.size();
for (int i = 0; i < 3; i++) {
as[i].resize(n); bs[i].resize(n);
}
if (a[0] == 'A') as[0][0]++;
if (b[0] == 'A') bs[0][0]++;
if (a[0] == 'T') as[1][0]++;
if (b[0] == 'T') bs[1][0]++;
if (a[0] == 'C') as[2][0]++;
if (b[0] == 'C') bs[2][0]++;
for (int i = 1; i < n; i++) {
for (int j = 0; j < 3; j++) {
as[j][i] = as[j][i-1];
bs[j][i] = bs[j][i-1];
}
if (a[i] == 'A') as[0][i]++;
if (b[i] == 'A') bs[0][i]++;
if (a[i] == 'T') as[1][i]++;
if (b[i] == 'T') bs[1][i]++;
if (a[i] == 'C') as[2][i]++;
if (b[i] == 'C') bs[2][i]++;
}
}
