#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
char c[] = {'A', 'C', 'T'};
int n;
int pre[N][3][3], preTwo[N][3][3], cnt[3][3], dem[3][3];
void init(string A, string B) {
n = A.size();
for (int i = 1; i <= n; i++) {
for (int j = 0; j < 3; j++)
for (int k = 0; k < 3; k++) {
pre[i][j][k] = pre[i-1][j][k] +
(A[i-1] != B[i-1] && A[i-1] == c[j] && B[i-1] == c[k]);
preTwo[i][j][k] = preTwo[i-1][j][k] +
(A[i-1] != B[i-1] && B[i-1] == c[j] && A[i-1] == c[k]);
}
}
}
int get_distance(int x, int y) {
x++; y++;
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) {
cnt[j][k] = pre[y][j][k] - pre[x-1][j][k];
dem[j][k] = preTwo[y][j][k] - preTwo[x-1][j][k];
}
if (cnt[j][0] + cnt[j][1] + cnt[j][2] !=
dem[j][0] + dem[j][1] + dem[j][2]) return -1;
}
int ans = 0;
// đổi chéo trực tiếp
for (int j = 0; j < 3; j++)
for (int k = 0; k < 3; k++) {
int temp = min(cnt[j][k], cnt[k][j]);
cnt[j][k] -= temp;
cnt[k][j] -= temp;
ans += temp;
}
bool ok = false;
for (int j = 0; j < 3; j++)
for (int k = 0; k < 3; k++) {
ans += cnt[j][k];
if (cnt[j][k]) ok = true;
}
ans -= ok; // trừ đi 1 nếu có chu trình 3 ký tự
return ans;
}
