#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+5;
int pa[2][N];
int pt[2][N];
int pc[2][N];
int pdif[N];
void init(std::string a, std::string b) {
int n = min(a.size(), b.size());
for (int i = 0; i < n; i++) {
pa[0][i] = (i == 0 ? 0 : pa[0][i-1]);
pt[0][i] = (i == 0 ? 0 : pt[0][i-1]);
pc[0][i] = (i == 0 ? 0 : pc[0][i-1]);
pa[1][i] = (i == 0 ? 0 : pa[1][i-1]);
pt[1][i] = (i == 0 ? 0 : pt[1][i-1]);
pc[1][i] = (i == 0 ? 0 : pc[1][i-1]);
pdif[i] = (i == 0 ? 0 : pdif[i-1]);
if (a[i] == 'A') pa[0][i]++;
if (a[i] == 'T') pt[0][i]++;
if (a[i] == 'C') pc[0][i]++;
if (b[i] == 'A') pa[1][i]++;
if (b[i] == 'T') pt[1][i]++;
if (b[i] == 'C') pc[1][i]++;
if (a[i] != b[i]) pdif[i]++;
}
}
int get_distance(int x, int y) {
int aa, ab, ta, tb, ca, cb, dif;
aa = pa[0][y] - (x == 0 ? 0 : pa[0][x-1]);
ab = pa[1][y] - (x == 0 ? 0 : pa[1][x-1]);
ta = pt[0][y] - (x == 0 ? 0 : pt[0][x-1]);
tb = pt[1][y] - (x == 0 ? 0 : pt[1][x-1]);
ca = pc[0][y] - (x == 0 ? 0 : pc[0][x-1]);
cb = pc[1][y] - (x == 0 ? 0 : pc[1][x-1]);
dif = pdif[y] - (x == 0 ? 0 : pdif[x-1]);
if (aa != ab || ta != tb || ca != cb) return -1;
if (!(aa && ta && ca)) {
return dif/2 + dif%2;
}
else {
int mn = min({aa, ta, ca});
return (dif-mn)/2 + mn + (y-x+1-mn)%2;
}
}
