#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
vector<int> pre[6];
void init(string a, string b) {
int n = a.size();
for (auto &vec : pre) vec.resize(n + 1);
for (int i = 0; i < n; i++) {
for (int j = 0; j < 6; j++) {
pre[j][i + 1] = pre[j][i];
}
if (a[i] == 'A' && b[i] == 'T') pre[0][i + 1]++;
if (a[i] == 'T' && b[i] == 'A') pre[3][i + 1]++;
if (a[i] == 'T' && b[i] == 'C') pre[1][i + 1]++;
if (a[i] == 'C' && b[i] == 'T') pre[4][i + 1]++;
if (a[i] == 'C' && b[i] == 'A') pre[2][i + 1]++;
if (a[i] == 'A' && b[i] == 'C') pre[5][i + 1]++;
}
}
int get_distance(int x, int y) {
int ans = 0, num[6];
for (int i = 0; i < 6; i++) {
num[i] = pre[i][y + 1] - pre[i][x];
}
for (int i = 0; i < 3; i++) {
int t = min(num[i], num[i + 3]);
ans += t, num[i] -= t, num[i + 3] -= t;
}
if (num[0] == num[1] && num[1] == num[2]) {
if (!num[3] && !num[4] && !num[5]) return ans + num[0] * 2;
}
if (num[3] == num[4] && num[4] == num[5]) {
if (!num[0] && !num[1] && !num[2]) return ans + num[3] * 2;
}
return -1;
}
