codeforce_problem/1742D_ Coprime at main · Arnob-sen/codeforce_problem · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

ll prime(ll x,ll y){
    if(__gcd(x,y)==1)return 1;

    return 0;
}

int main()
{
    ll t;
    cin>>t;
    while(t--){
        ll n;
        cin>>n;
        ll arr[n+1],a[10000]={0};
        map<ll,ll>m;
        vector<pair<ll,ll>>v,x;

        for(ll i=0;i<n;i++){
            cin>>arr[i];
            v.push_back({arr[i],i});


        }
        for(ll i=n-1;i>=0;i--){
            if(a[v[i].first]==0)x.push_back({v[i].first,v[i].second});
            a[v[i].first]=1;
        }
      //  for(ll i=0;i<x.size();i++)cout<<x[i].first<<" "<<x[i].second<<endl;

ll mp=-1;

              for(ll i=0;i<x.size();i++){
            for(ll j=i;j<x.size();j++){
                if(prime(x[i].first,x[j].first))mp=max(mp,x[i].second+x[j].second);
            }

        }
        if(mp==-1)
        cout<<mp<<endl;
        else cout<<mp+2<<endl;;


    }
    return 0;
}