AP Free Sequences.cpp

/*
  ***** !!!!! JAI SHREE KRISHNA !!!!! *****
  
  Date - 17th May 2023
  Code by - Abhinav Anand

  Problem link -> https://www.codechef.com/START90D/problems/THREEAPFREE

*/

#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
#define ll long long int
#define endl "\n"
using namespace std;
int N=1000001;
vector<int> arr(N,true);
vector<int> prime_num;
vector<int> prime_fact(N,-1);

void sieve()
{
    
    arr[0]=arr[1]=0;
    for(int i=2;i<=sqrt(N);i++)
    {
        if(arr[i]==1)
        {
            for(int j=i*i;j<=N;j+=i)
                arr[j]=0;
        }
    }
    
    for(int i=2;i<=N;i++)
    {
        if(arr[i])
            prime_num.push_back(i);
    }
}

void sieve_prime_factor()
{
    
    for(int i=2;i<=N;i++)
    {
        if(prime_fact[i]==-1)
        {
            for(int j=i;j<=N;j+=i)
            {
                // if(prime_fact[j]==-1)
                    prime_fact[j]=i;
            }
        }
    }
    
    int k;
    cin>>k;
    while(k>1)
    {
        cout << prime_fact[k] << " ";
        k=k/prime_fact[k];
    }
}

bool isprime(int n)
{
    for(int i=2;i<=sqrt(n);i++)
    {
        if(n%i==0)
            return false;
    }
    return true;
}


void solve()
{
    int n;
    cin>>n;
    int a[n];
    for(int i=0;i<n;i++)
        cin>>a[i];
    
    bool ans=false;
    int d = a[1] - a[0];
    for(int i=0;i<n-2;i++)
    {
        for(int j=i+1;j<n-1;j++)
        {
            for(int k=j+1;k<n;k++)
            {
                if((a[j]-a[i])==(a[k]-a[j]))
                {
                    ans=true;
                    break;
                }
            }
            if(ans==true)
                break;
        }
        if(ans==true)
            break;
    }
    
    if(ans==true)
        cout << "No" << endl;
    else
        cout << "Yes" << endl;
}

int main() {
	
	//sieve_prime_factor();
	// sieve();
	int t;
	cin>>t;
	while(t--)
	{
		solve();
	}
	return 0;
}