#include "dna.h"
#include<bits/stdc++.h>
using namespace std;
int n;
vector<vector<int>>c1,c2,cnt;
vector<int>dp;
void init(std::string a, std::string b) {
n=a.size();
dp.resize(n+1);
dp[0]=0;
c1.assign(n+1,vector<int>(26,0));
c2=c1;
cnt.assign(n+1,vector<int>(6,0));
for(int i=0;i<n;i++){
dp[i+1]=dp[i]+(a[i]==b[i]);
// cout<<dp[i+1]<<' ';
c1[i+1]=c1[i];
c1[i+1][a[i]-'A']++;
c2[i+1]=c2[i];
c2[i+1][b[i]-'A']++;
cnt[i+1]=cnt[i];
if(a[i]=='A'){
if(b[i]=='C') cnt[i+1][0]++;
if(b[i]=='T') cnt[i+1][1]++;
}
if(a[i]=='C'){
if(b[i]=='A') cnt[i+1][2]++;
if(b[i]=='T') cnt[i+1][3]++;
}
if(a[i]=='T'){
if(b[i]=='A') cnt[i+1][4]++;
if(b[i]=='C') cnt[i+1][5]++;
}
// for(int j=0;j<6;j++) cout<<cnt[i+1][j]<<" \n"[j==5];
}
}
int get_distance(int x, int y) {
for(int i=0;i<26;i++) if(c1[y+1][i]-c1[x][i]!=c2[y+1][i]-c2[x][i]) return -1;
auto g=cnt[y+1];
for(int i=0;i<6;i++) g[i]-=cnt[x][i];
int ans=min(g[0],g[2])+min(g[1],g[4])+min(g[3],g[5])+(abs(g[0]-g[2])+abs(g[1]-g[4])+abs(g[3]-g[5]))/3*2;
return ans;
}
