#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 100005;
int prea[maxn], prec[maxn], pret[maxn];
int prea1[maxn], prec1[maxn], pret1[maxn];
int preac[maxn], preca[maxn], preat[maxn], preta[maxn], prect[maxn], pretc[maxn];
int n;
void init(std::string a, std::string b) {
memset(prea, 0, sizeof(prea));
memset(prec, 0, sizeof(prec));
memset(pret, 0, sizeof(pret));
memset(prea1, 0, sizeof(prea1));
memset(prec1, 0, sizeof(prec1));
memset(pret1, 0, sizeof(pret1));
memset(preac, 0, sizeof(preac));
memset(preca, 0, sizeof(preca));
memset(preat, 0, sizeof(preat));
memset(preta, 0, sizeof(preta));
memset(prect, 0, sizeof(prect));
memset(pretc, 0, sizeof(pretc));
n = a.length();
for (int i=0;i<n;++i) {
int j = i+1;
prea[j] = prea[j-1];
prec[j] = prec[j-1];
pret[j] = pret[j-1];
prea1[j] = prea1[j-1];
prec1[j] = prec1[j-1];
pret1[j] = pret1[j-1];
preac[j] = preac[j-1];
preca[j] = preca[j-1];
preat[j] = preat[j-1];
preta[j] = preta[j-1];
prect[j] = prect[j-1];
pretc[j] = pretc[j-1];
if (a[i] == 'A') prea[j] += 1;
if (b[i] == 'A') prea1[j] += 1;
if (a[i] == 'C') prec[j] += 1;
if (b[i] == 'C') prec1[j] += 1;
if (a[i] == 'T') pret[j] += 1;
if (b[i] == 'T') pret1[j] += 1;
if (a[i] == 'A' && b[i] == 'C') preac[j] += 1;
if (a[i] == 'C' && b[i] == 'A') preca[j] += 1;
if (a[i] == 'A' && b[i] == 'T') preat[j] += 1;
if (a[i] == 'T' && b[i] == 'A') preta[j] += 1;
if (a[i] == 'C' && b[i] == 'T') prect[j] += 1;
if (a[i] == 'T' && b[i] == 'C') pretc[j] += 1;
}
}
int get_distance(int x, int y) {
x += 1;
y += 1;
if (prea[y] - prea[x-1] != prea1[y] - prea1[x-1]) return -1;
if (prec[y] - prec[x-1] != prec1[y] - prec1[x-1]) return -1;
if (pret[y] - pret[x-1] != pret1[y] - pret1[x-1]) return -1;
int tot = y-x+1;
int acm = min(preac[y]-preac[x-1], preca[y]-preca[x-1]);
int atm = min(preat[y]-preat[x-1], preta[y]-preta[x-1]);
int ctm = min(prect[y]-prect[x-1], pretc[y]-pretc[x-1]);
tot -= 2*acm;
tot -= 2*atm;
tot -= 2*ctm;
int ans = acm+atm+ctm;
ans += tot / 3 * 2;
return ans;
}
// int main() {
// init("ATACAT", "ACTATA");
// std::cout << get_distance(1, 3) << std::endl;
// std::cout << get_distance(4, 5) << std::endl;
// std::cout << get_distance(3, 5) << std::endl;
// return 0;
// }
