#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
int a[100100][2] = {0}, t[100100][2] = {0}, c[100100][2] = {0};
int at[100100] = {0}, ac[100100] = {0}, tc[100100] = {0};
void analyse(string& s, int p){
for(int i = 0; i < s.size(); ++i){
a[i + 1][p] = a[i][p];
t[i + 1][p] = t[i][p];
c[i + 1][p] = c[i][p];
if(s[i] == 'A'){
++a[i + 1][p];
}
if(s[i] == 'T'){
++t[i + 1][p];
}
if(s[i] == 'C'){
++c[i + 1][p];
}
}
}
void init(std::string s1, std::string s2) {
analyse(s1, 0);
analyse(s2, 1);
for(int i = 0; i < s1.size(); ++i){
at[i + 1] = at[i];
ac[i + 1] = ac[i];
tc[i + 1] = tc[i];
if(s1[i] != s2[i]){
string q;
q.push_back(s1[i]); q.push_back(s2[i]);
sort(begin(q), end(q));
if(q == "AT"){
++at[i + 1];
}
if(q == "AC"){
++ac[i + 1];
}
if(q == "CT"){
++tc[i + 1];
}
}
}
}
int sum(int x, int y, int t[][2], int p){
return t[y][p] - t[x - 1][p];
}
int sum2(int x, int y, int t[]){
return t[y] - t[x - 1];
}
int get_distance(int x, int y) {
++x, ++y;
if(sum(x, y, a, 0) == sum(x, y, a, 1) && sum(x, y, t, 0) == sum(x, y, t, 1) && sum(x, y, c, 0) == sum(x, y, c, 1)){
ll sol = sum2(x, y, at) / 2 + sum2(x, y, ac) / 2 + sum2(x, y, tc) / 2;
if(sum2(x, y, at) % 2 == 1){
sol += 2;
}
return sol;
}
return -1;
}
