#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
string a, b;
vector<vector<int>> ama, amb;
vector<int> pref;
void init(std::string A, std::string B) {
a = A, b = B;
int n = a.size();
pref.assign(n, 0);
ama.assign(n, vector<int>(3, 0));
amb = ama;
map<char, int> mp;
mp['A'] = 0;
mp['C'] = 1;
mp['T'] = 2;
for (int i=0; i<n; i++) {
int at = (i==0 ? 0 : pref[i-1]);
pref[i] = at + (a[i]!=b[i]);
for (int j=0; j<3; j++) {
int at = (i==0 ? 0 : ama[i-1][j]);
ama[i][j] = at;
at = (i==0 ? 0 : amb[i-1][j]);
amb[i][j] = at;
}
ama[i][mp[a[i]]]++;
amb[i][mp[b[i]]]++;
}
}
int get_distance(int x, int y) {
int det = (x==0 ? 0 : pref[x-1]);
int cnt = pref[y]-det;
//calcular apariciones de A
det = (x==0 ? 0 : ama[x-1][0]);
int A = ama[y][0] - det;
det = (x==0 ? 0 : amb[x-1][0]);
int B = amb[y][0] - det;
if (A!=B) return -1;
//calcular apariciones de T
det = (x==0 ? 0 : ama[x-1][2]);
A = ama[y][2] - det;
det = (x==0 ? 0 : amb[x-1][2]);
B = amb[y][2] - det;
if (A!=B) return -1;
return cnt/2;
}
