Help me in solving LPC problem

help
,
1

My issue

I need hint for solving

My code

#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define repr(i,b,a) for(ll i=b;i>=a;i--)
#define ppi pair<ll,ll> 
#define ppc __builtin_popcount
#define ppcll __builtin_popcountll
#define sz(x) (ll) x.size()
#define fast1 ios_base::sync_with_stdio(false)
#define fast2 cin.tie(0)
const ll mod = 1e9+7;




void solve(){
    
   int n,m;
   cin>>n>>m;
   string s;
   string k;
   cin>>s;
   cin>>k;
   
   
   int i=0;
   int j=0;
   int res=INT_MAX;
   int cnt=0;
   while(j<n){
       if(j-i+1>m){
           i++;
       }
       if(j-i+1==m){
           res=min(res,cnt);
       }
       
       j++;
   }
    
    
}



int main()
{
    fast1;
    fast2;
    ll t;
    cin>>t;
    while(t--){
    solve();
    }
}

Problem Link: LPC Problem - CodeChef

2

@mahesh_024
U can apply brute force in this problem.
Plzz refer the following solution for better understanding of logic.

#include<bits/stdc++.h>
#define ll long long 
#define endl "\n"
// constant
const int mod = 1e9+7;
using namespace std;
 
int main(){
    int t;  cin>>t;
    while(t--){
        int n,m;
        cin>>n>>m;
        string s,k;
        cin>>s>>k;
        int cnt = 0;
        int ans = INT_MAX;
        int j = 0; 
        for(int i = 0; i<n-m+1; i++){
            for(int j = 0; j<m; j++){
                int x= abs(s[i+j]-k[j]);
                if(x>5){
                    x = 10 - x;
                }
                cnt += x;
            }
            ans = min(ans,cnt);
            cnt = 0;
        }
        cout<<ans<<endl;
    }
    return 0;
}