Why I'm getting TLE in TRIPLETMIN problem

[labu_1011]

My issue

My code

#include <bits/stdc++.h>

typedef long long int ll;
using namespace std;


void solve() {
    int t;
    cin >> t;

    while (t--)
    {
        ll n, q;
        cin >> n >> q;

        ll arr[n];
        for(int i = 0; i < n; i++) {
            cin >> arr[i];
        }

        sort(arr, arr+n);

        vector<ll> v(n);
        for(int i = 0; i < n; i++) {
            v[i] = ((n-i-1) * (n-i-2)) / 2;
            if(i > 0) v[i] += v[i-1];
        }

        while(q--) {
            int m;
            cin >> m;

            cout << arr[lower_bound(v.begin(), v.end(), m) - v.begin()] << endl;
        }
        
    }
    
}



int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif

    solve();
    return 0;
}

Problem Link: TRIPLETMIN Problem - CodeChef