#include <bits/stdc++.h>
#include "dna.h"
using namespace std;
vector<vector<int>>v;
vector<vector<int>>cntA,cntB;
int T(char a, char b) {
if(a == 'A' && b == 'T')
return 0;
if(a == 'T' && b == 'A')
return 1;
if(a == 'C' && b == 'T')
return 2;
if(a == 'T' && b == 'C')
return 3;
if(a == 'C' && b == 'A')
return 4;
if(a == 'A' && b == 'C')
return 5;
return 100;
}
void init(string a, string b) {
const int n = (int)a.length();
v.resize(n+1, vector<int>(6,0));
cntA.resize(n+1, vector<int>(3, 0));
cntB.resize(n+1, vector<int>(3, 0));
for(int i = 1 ; i <= n ; i++) {
for(int j = 0 ; j < 6 ; j++) {
v[i][j] = v[i-1][j];
if(T(a[i-1], b[i-1]) == j)
v[i][j]++;
}
}
for(int i = 1 ; i <= n ; i++) {
for(int j = 0 ; j < 3 ; j++) {
cntA[i][j] = cntA[i-1][j];
cntB[i][j] = cntB[i-1][j];
if(j == 0 && a[i-1] == 'A')
cntA[i][j]++;
if(j == 1 && a[i-1] == 'T')
cntA[i][j]++;
if(j == 2 && a[i-1] == 'C')
cntA[i][j]++;
if(j == 0 && b[i-1] == 'A')
cntB[i][j]++;
if(j == 1 && b[i-1] == 'T')
cntB[i][j]++;
if(j == 2 && b[i-1] == 'C')
cntB[i][j]++;
}
}
}
int get_distance(int x, int y) {
x++,y++;
vector<int>t(6);
for(int i = 0 ; i < 6 ; i++)
t[i] = v[y][i] - v[x-1][i];
for(int i = 0 ; i < 3 ; i++) {
if(cntA[y][i] - cntA[x-1][i] != cntB[y][i] - cntB[x-1][i])
return -1;
}
int ans = 0;
for(int i = 0 ; i < 6 ; i += 2) {
int mn = min(t[i], t[i+1]);
ans += mn;
t[i] -= mn, t[i+1] -= mn;
}
int total = 0;
for(auto z : t)
total += z;
if(total%3)
return -1;
ans += (total/3) * 2;
return ans;
}
