1433C-Dominant_Piranha.cpp

/*
    written by Pankaj Kumar.
    country:-INDIA
*/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef vector<ll> vl;
typedef vector<bool> vb;
typedef vector<char> vc;
typedef map<ll,ll> ml;
typedef set<char>sc;
typedef set<ll> sl;
#define pan cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
// define values.
#define mod 1000000007
#define phi 1.618
/* Bit-Stuff */
#define get_set_bits(a) (__builtin_popcount(a))
#define get_set_bitsll(a) ( __builtin_popcountll(a))
#define get_trail_zero(a) (__builtin_ctz(a))
#define get_lead_zero(a) (__builtin_clz(a))
#define get_parity(a) (__builtin_parity(a))
/*  Abbrevations  */
#define ff first
#define ss second
#define mp make_pair
#define line cout<<endl;
#define pb push_back
#define Endl "\n"
// loops
#define forin(arr,n) for(ll i=0;i<n;i++) cin>>arr[i];
// Some print
#define no cout<<"NO"<<endl;
#define yes cout<<"YES"<<endl;
#define cc ll test;cin>>test;while(test--)
// sort
#define all(V) (V).begin(),(V).end()
#define srt(V) sort(all(V))
#define srtGreat(V) sort(all(V),greater<ll>())
// function

ll power(ll x,ll y)
{
    ll res=1;
    // x=x%mod;
    while(y>0)
    {
        if(y%2==1)
        {
            res*=x;
            // res=res%mod;
        }
        y/=2; x*=x; // x=x%mod;
    }
    return res;
}
/* ascii value 
A=65,Z=90,a=97,z=122
*/
/*  -----------------------------------------------------------------------------------*/


ll solve()
{
    ll n;
    cin>>n;
    set<ll> s;
    ll maxo=0;
    vector<pair<ll,ll>> v(n);
    for(ll i=0;i<n;i++)
    {
        ll temp;
        cin>>temp;
        v[i]={temp,i+1};
        s.insert(temp);
        maxo=max(maxo,temp);
    }
    if(s.size()==1)
    {
        cout<<-1<<endl;
        return 0;
    }
    else
    {
        // ll ans=0;
        // srt(v);
        for(ll i=1;i<n;i++)
        {
            if(v[i].ff==maxo&&v[i-1].ff!=maxo)
            {
                // cout<<" hi ";
                cout<<v[i].ss<<endl;
                return 0;
            }
        }
        for(ll i=0;i+1<n;i++)
        {
            if(v[i].ff==maxo&&v[i+1].ff!=maxo)
            {
                cout<<v[i].ss<<endl;
                return 0;
            }
        }
    }
    return 0;
}

int main()
{
    //freopen("input.txt"a, "r", stdin);
    pan;
    // solve();
    cc
    {
        solve();
    }
}