Chef and Minimum Colouring TLE

#include<bits/stdc++.h>
using namespace std;
vector<int>v[100005];
int ans,m;
void solve(int p,int mn,int mx){
    if (mx-mn>=ans) return;
    if (p==m){
        ans=min(ans,mx-mn);
        return;
    }
    for (int i=0; i<v[p].size(); i++){
        if (v[p][i]<mn) solve(p+1,v[p][i],mx);
        else if (v[p][i]>mx) solve(p+1,mn,v[p][i]);
        else solve(p+1,mn,mx);
    }
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    int t,n,i,x;
    cin>>t;
    while(t--){
        cin>>n>>m;
        for (i=0; i<m; i++)v[i].clear();
        for (i=0; i<n; i++){
            cin>>x;
            v[i%m].push_back(x);
        }
        ans=1e9;
        for (i=0; i<v[0].size(); i++)
            solve(1,v[0][i],v[0][i]);
        cout<<ans<<endl;
    }
    return 0;
}