#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 100000;
int diff[N];
int Aa[N];
int Ca[N];
int Ab[N];
int Cb[N];
int ind(char c)
{
if(c == 'A')
{
return 0;
}
else if(c == 'C')
{
return 1;
}
return 2;
}
int adjlist[N][3][3]; //Letter string a, letter string b
void init(std::string a, std::string b)
{
Aa[0] = (a[0] == 'A');
Ca[0] = (a[0] == 'C');
Ab[0] = (b[0] == 'A');
Cb[0] = (b[0] == 'C');
for(int c = 0; c < 3; c++)
{
for(int d = 0; d < 3; d++)
{
adjlist[0][c][d] = 0;
}
}
adjlist[0][ind(a[0])][ind(b[0])] = 1;
int n = a.length();
for(int i = 1; i < n; i++)
{
Aa[i] = Aa[i-1]+(a[i] == 'A');
Ca[i] = Ca[i-1]+(a[i] == 'C');
Ab[i] = Ab[i-1]+(b[i] == 'A');
Cb[i] = Cb[i-1]+(b[i] == 'C');
for(int c = 0; c < 3; c++)
{
for(int d = 0; d < 3; d++)
{
adjlist[i][c][d] = adjlist[i-1][c][d];
}
}
adjlist[i][ind(a[i])][ind(b[i])]++;
}
}
int get_distance(int x, int y)
{
if(Aa[y] - (x == 0 ? 0 : Aa[x-1]) != Ab[y] - (x== 0 ? 0 : Ab[x-1]) ||
Ca[y] - (x == 0 ? 0 : Ca[x-1]) != Cb[y] - (x== 0 ? 0 : Cb[x-1]))
{
return -1;
}
int counter[3][3];
for(int c = 0; c < 3; c++)
{
for(int d = 0; d < 3; d++)
{
counter[c][d] = adjlist[y][c][d] - (x == 0 ? 0 : adjlist[x-1][c][d]);
}
}
int output = 0;
for(int i = 0; i < 3; i++)
{
counter[i][i] = 0;
for(int j = 0; j < 3; j++)
{
if(i == j) continue;
int m = min(counter[i][j], counter[j][i]);
counter[i][j] -= m;
counter[j][i] -= m;
output += m;
}
}
output += max(counter[0][1], counter[0][2])*2;
return output;
}
