#include <bits/stdc++.h>
#include "dna.h"
using namespace std;
const int MAXN = 1e5 + 7;
int word1[MAXN];
int word2[MAXN];
int pref[MAXN][3][3];
void init(string a, string b){
int n = a.size();
for(int i = 0; i < n; i++){
if(a[i] == 'A')
word1[i + 1] = 0;
if(a[i] == 'T')
word1[i + 1] = 1;
if(a[i] == 'C')
word1[i + 1] = 2;
if(b[i] == 'A')
word2[i + 1] = 0;
if(b[i] == 'T')
word2[i + 1] = 1;
if(b[i] == 'C')
word2[i + 1] = 2;
}
for(int i = 1; i <= n; i++){
for(int c1 = 0; c1 < 3; c1++){
for(int c2 = 0; c2 < 3; c2++){
if((word1[i] == c1) && (word2[i] == c2))
pref[i][c1][c2] = pref[i - 1][c1][c2] + 1;
else
pref[i][c1][c2] = pref[i - 1][c1][c2] + 0;
}
}
}
}
int get_distance(int x, int y){
x = x + 1;
y = y + 1;
// 0 - A, 1 - T, 2 - C
// 0 -> 1 (zamiana A na T)
int AT = pref[y][0][1] - pref[x - 1][0][1];
int TA = pref[y][1][0] - pref[x - 1][1][0];
int TC = pref[y][1][2] - pref[x - 1][1][2];
int CT = pref[y][2][1] - pref[x - 1][2][1];
int CA = pref[y][2][0] - pref[x - 1][2][0];
int AC = pref[y][0][2] - pref[x - 1][0][2];
if((AT + AC == TA + CA) && (TA + TC == AT + CT)){
int ans = min(AT, TA) + min(TC, CT) + min(CA, AC);
ans += 2 * abs(AT - TA);
return ans;
}
else return -1;
}
