View Code of Problem 6

#include <bits/stdc++.h>
using namespace std;
bool cmp(int a, int b) {
    return a > b;
}
int main() {
    int T, n, l, r, a, b;
    scanf("%d", &T);
    for (int i = 0; i < T; i++) {
        scanf("%d", &n);
        vector<int> v1, v2;
        bool onOff = true;
        for (int j = 0; j < n; j++) {
            scanf("%d %d", &a, &b);
            v1.push_back(b - a);
            v2.push_back(a);
            v2.push_back(b);
        }
        sort(v1.begin(), v1.end(), cmp);
        for (int i = 0; i < v2.size(); i+=2) {
            if(v2[i] + v1[0] > v2[i + 1]) {
                onOff = false;
                break;
            }
        }
        if(onOff)
            printf("YES\n");
        else
            printf("NO\n");
    }
    return 0;
}