#include <bits/stdc++.h>
#include "dna.h"
using namespace std;
#define lim 100005
int n;
int pre_a_a[lim],pre_b_a[lim];// a string a char ----- b string a char
int pre_a_t[lim],pre_b_t[lim];// a string t char ----- b string t char
int pre_a_c[lim],pre_b_c[lim];// a string c char ----- b string c char
int sum[lim];
inline bool querya(int x,int y){
if(pre_a_a[y+1]-pre_a_a[x]==pre_b_a[y+1]-pre_b_a[x])return 1;
return 0;
}
inline bool queryt(int x,int y){
if(pre_a_t[y+1]-pre_a_t[x]==pre_b_t[y+1]-pre_b_t[x])return 1;
return 0;
}
inline bool queryc(int x,int y){
if(pre_a_c[y+1]-pre_a_c[x]==pre_b_c[y+1]-pre_b_c[x])return 1;
return 0;
}
void init(string a,string b) {
n=a.length();
for(int i=0;i<n;i++){
pre_a_a[i+1]=pre_a_a[i];
if(a[i]=='A')pre_a_a[i+1]++;
pre_b_a[i+1]=pre_b_a[i];
if(b[i]=='A')pre_b_a[i+1]++;
pre_a_t[i+1]=pre_a_t[i];
if(a[i]=='T')pre_a_t[i+1]++;
pre_b_t[i+1]=pre_b_t[i];
if(b[i]=='T')pre_b_t[i+1]++;
pre_a_c[i+1]=pre_a_c[i];
if(a[i]=='C')pre_a_c[i+1]++;
pre_b_c[i+1]=pre_b_c[i];
if(b[i]=='C')pre_b_c[i+1]++;
sum[i+1]=sum[i];
if(a[i]!=b[i])sum[i+1]++;
}
}
int get_distance(int x, int y) {
if(y-x<=2){
if(querya(x,y) && queryt(x,y) && queryc(x,y)){
int tut=sum[y+1]-sum[x];
if(tut==3)return 2;
else if(tut==2)return 1;
else if(tut==1)return 1;
else return 0;
}
else return -1;
}
else{
if(querya(x,y) && queryt(x,y)){
return (sum[y+1]-sum[x])/2;
}
else return -1;
}
}
