#include <bits/stdc++.h>
using namespace std;
#include "dna.h"
using namespace std;
vector<int> A_a, C_a, T_a;
vector<int> A_b, C_b, T_b;
void init(string a, string b) {
int n = a.size();
A_a = C_a = T_a = vector<int>(n + 1, 0);
A_b = C_b = T_b = vector<int>(n + 1, 0);
for (int i = 1; i <= n; ++i) {
A_a[i] = A_a[i - 1] + (a[i - 1] == 'A');
C_a[i] = C_a[i - 1] + (a[i - 1] == 'C');
T_a[i] = T_a[i - 1] + (a[i - 1] == 'T');
A_b[i] = A_b[i - 1] + (b[i - 1] == 'A');
C_b[i] = C_b[i - 1] + (b[i - 1] == 'C');
T_b[i] = T_b[i - 1] + (b[i - 1] == 'T');
}
}
int get_distance(int x, int y) {
int a_count_A = A_a[y + 1] - A_a[x];
int a_count_C = C_a[y + 1] - C_a[x];
int a_count_T = T_a[y + 1] - T_a[x];
int b_count_A = A_b[y + 1] - A_b[x];
int b_count_C = C_b[y + 1] - C_b[x];
int b_count_T = T_b[y + 1] - T_b[x];
if (a_count_A != b_count_A || a_count_C != b_count_C || a_count_T != b_count_T) {
return -1;
}
int makanch_AC = abs(a_count_A - b_count_A);
int makanch_AT = abs(a_count_A - b_count_T);
int makanch_CT = abs(a_count_C - b_count_T);
int direct_swaps = makanch_AC / 2 + makanch_AT / 2 + makanch_CT / 2;
int two_step_swaps = (makanch_AC % 2) + (makanch_AT % 2) + (makanch_CT % 2);
return direct_swaps + 2 * two_step_swaps;
}
