B_Diameter_of_Graph.cpp

    #include <bits/stdc++.h>
    using namespace std;
    // First you make it work, then you can always make it beautiful
    #define int long long

    void solve() {
        int n, m, k;
        cin >> n >> m >> k;
        if(m > n*(n-1)/2 || m < n - 1) {
            cout << "NO\n";
            return;
        }
        if(n == 1) {
            if(k > 1) cout << "YES\n";
            else cout << "NO\n";
            return;
        }
        if(k <= 2) {
            cout << "NO\n";
            return;
        }
        if(k == 3) {
            if(m == n*(n-1)/2) cout << "YES\n";
            else cout << "NO\n";
            return;
        }

        cout << "YES\n";

    }


    int32_t main(){
        ios_base::sync_with_stdio(false);
        cin.tie(nullptr);
        cout.tie(nullptr);

        int _;
        cin >> _;
        while (_-->0) {
            solve();
        }

        return 0;
    }