#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> cnt[3][3];
int mp[256];
void init(string a, string b)
{
mp['A'] = 0; mp['T'] = 1; mp['C'] = 2;
n = a.length();
for (int i = 0; i != 3; i ++)
for (int j = 0; j != 3; j ++)
cnt[i][j].resize(n + 1);
for (int i = 0; i != n; i ++)
{
int u = mp[a[i]], v = mp[b[i]];
for (int j = 0; j != 3; j ++)
for (int k = 0; k != 3; k ++)
cnt[j][k][i + 1] = cnt[j][k][i] + (j == u && k == v);
}
}
int get_distance(int x, int y)
{
int ans = 0, cyc = -1;
for (int i = 0; i != 3; i ++)
{
int j = (i + 1) % 3;
int a = cnt[i][j][y + 1] - cnt[i][j][x];
int b = cnt[j][i][y + 1] - cnt[j][i][x];
if (i == 0)
cyc = a - b;
else if (cyc != a - b)
return -1;
ans += min(a, b);
}
return ans + 2 * abs(cyc);
}
