#include "dna.h"
#include <vector>
using namespace std;
vector<int> AC, AT, CA, CT, TA, TC;
void init(std::string a, std::string b) {
int n = a.size();
AC.resize(n+1);
AT.resize(n+1);
CA.resize(n+1);
CT.resize(n+1);
TA.resize(n+1);
TC.resize(n+1);
for (int i = 0; i < n; i++) {
if (a[i] == 'A' && b[i] == 'C') AC[i+1] = AC[i] + 1;
if (a[i] == 'A' && b[i] == 'T') AT[i+1] = AT[i] + 1;
if (a[i] == 'C' && b[i] == 'A') CA[i+1] = CA[i] + 1;
if (a[i] == 'C' && b[i] == 'T') CT[i+1] = CT[i] + 1;
if (a[i] == 'T' && b[i] == 'A') TA[i+1] = TA[i] + 1;
if (a[i] == 'T' && b[i] == 'C') TC[i+1] = TC[i] + 1;
}
}
int get_distance(int x, int y) {
int ac = AC[y+1] - AC[x];
int at = AT[y+1] - AT[x];
int ca = CA[y+1] - CA[x];
int ct = CT[y+1] - CT[x];
int ta = TA[y+1] - TA[x];
int tc = TC[y+1] - TC[x];
if(ac + at != ca + ta) return -1;
if(ca + ct != ta + tc) return -1;
if(ta + tc != ac + at) return -1;
int ans = 0;
ans += ac + at + ca + ct + ta + tc;
ans += min(ac, ca) + min(at, ta) + min(ct, tc) + 2 * abs(ac - ca);
return ans;
}
