#include "dna.h"
#include <bits/stdc++.h>
int sum[100001][3][3];
void init(std::string a, std::string b) {
const int n = (int)a.size();
for (int i = 0; i < n; ++i) {
const int x = a[i] == 'A' ? 0 : (a[i] == 'C' ? 1 : 2);
const int y = b[i] == 'A' ? 0 : (b[i] == 'C' ? 1 : 2);
sum[i + 1][x][y] += 1;
for (int j = 0; j < 3; ++j) {
for (int k = 0; k < 3; ++k) {
sum[i + 1][j][k] += sum[i][j][k];
}
}
}
}
int get_distance(int l, int r) {
int dif[3][3];
for (int j = 0; j < 3; ++j) {
for (int k = 0; k < 3; ++k) {
dif[j][k] = sum[r + 1][j][k] - sum[l][j][k];
}
}
int ret = 0;
for (int i = 0; i < 3; ++i) {
const int j = i == 2 ? 0 : i + 1;
const int min = std::min(dif[i][j], dif[j][i]);
ret += min;
dif[i][j] -= min;
dif[j][i] -= min;
}
if (dif[0][1] == dif[1][2] and dif[1][2] == dif[2][0] and dif[1][0] == dif[2][1] and dif[2][1] == dif[0][2]) {
return ret + (dif[0][1] + dif[1][0]) * 2;
} else {
return -1;
}
}
