#include "dna.h"
#include<bits/stdc++.h>
#define N 100005
using namespace std;
int a[N][3],b[N][3],dif[N],len;
void init(string x, string y) {
len = x.size();
for(int i=0;i<len;i++){
if(i != 0) for(int j=0;j<=2;j++) a[i][j] = a[i-1][j], b[i][j] = b[i-1][j];
if(i != 0) dif[i] = dif[i-1];
if(x[i] == 'A') a[i][0]++;
else if(x[i] == 'T') a[i][1]++;
else if(x[i] == 'C') a[i][2]++;
if(y[i] == 'A') b[i][0]++;
else if(y[i] == 'T') b[i][1]++;
else if(y[i] == 'C') b[i][2]++;
if(x[i] != y[i]) dif[i]++;
}
}
int get_distance(int x, int y) {
int A[3], B[3], D;
for(int i=0;i<=2;i++) A[i] = a[y][i], B[i] = b[y][i];
if(x != 0) for(int i=0;i<=2;i++) A[i] -= a[x-1][i], B[i] -= b[x-1][i];
for(int i=0;i<=2;i++) if(A[i] != B[i]) return -1;
D = dif[y];
if(x != 0) D -= dif[x-1];
return D ? D-1 : 0;
}
