1909A - Distinct Buttons - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int mod = 1e9 + 7;
#define pb push_back
#define en cout << endl;
#define yes cout << "YES" << '\n';
#define no cout << "NO" << '\n';
#define FARIA                     \
    ios_base::sync_with_stdio(0); \
    cin.tie(0);                   \
    cout.tie(0);
#define cin(x)        \
    for (auto &i : x) \
        cin >> i;
#define cout(x)       \
    for (auto &i : x) \
        cout << i << " ";
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define N 10010

int main()
{
    FARIA
    int t = 1;
    cin >> t;
    while (t--)
    {
        ll n, x, y, a, b, c, d;
        cin >> n;
        a = b = c = d = 0;
        for (ll i = 0; i < n; i++)
        {
            cin >> x >> y;
            if (x > 0)
            {
                a = 1;
            }
            if (y > 0)
            {
                b = 1;
            }
            if (x < 0)
            {
                c = 1;
            }
            if (y < 0)
            {
                d = 1;
            }
        }
        if (a + b + c + d < 4)
        {
            yes;
        }
        else
        {
            no;
        }
    }

    return 0;
}