#include "dna.h"
#include <bits/stdc++.h>
using namespace std;
int n;
int asum[100050][3], bsum[100050][3];
int cnt[100050][3][3];
void init(std::string a, std::string b){
n = (int)a.size();
for(int i = 0; i < n; i ++){
if(a[i] == 'A') asum[i + 1][0] ++;
else if(a[i] == 'C') asum[i + 1][1] ++;
else asum[i + 1][2] ++;
if(b[i] == 'A') bsum[i + 1][0] ++;
else if(b[i] == 'C') bsum[i + 1][1] ++;
else bsum[i + 1][2] ++;
int ai = 2, bi = 2;
if(a[i] == 'A') ai = 0;
else if(a[i] == 'C') ai = 1;
if(b[i] == 'A') bi = 0;
else if(b[i] == 'C') bi = 1;
cnt[i + 1][ai][bi] = 1;
}
for(int i = 2; i <= n; i ++){
for(int j = 0; j < 3; j ++){
asum[i][j] += asum[i - 1][j];
bsum[i][j] += bsum[i - 1][j];
}
for(int j = 0; j < 3; j ++){
for(int jj = 0; jj < 3; jj ++){
cnt[i][j][jj] += cnt[i - 1][j][jj];
}
}
}
}
int get_distance(int x, int y){
x++, y++;
for(int j = 0; j < 3; j ++){
if(asum[y][j] - asum[x - 1][j] != bsum[y][j] - bsum[x - 1][j]){
return -1;
}
}
int c[3][3] = {{0}};
for(int j = 0; j < 3; j ++){
for(int jj = 0; jj < 3; jj ++){
c[j][jj] = cnt[y][j][jj] - cnt[x - 1][j][jj];
}
}
int tmp = min(c[0][1], c[1][0]), ans = 0;
c[0][1] -= tmp, c[1][0] -= tmp, ans += tmp;
tmp = min(c[0][2], c[2][0]);
c[0][2] -= tmp, c[2][0] -= tmp, ans += tmp;
tmp = min(c[1][2], c[2][1]);
c[1][2] -= tmp, c[2][1] -= tmp, ans += tmp;
ans += 2 * (c[0][1] + c[1][0]);
return ans;
}
// aaaacccctt
// ccccaattaa
