View Code of Problem 6

#include<stdio.h>
#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>
#include<stack>
using namespace std;
struct jihe {
	int first;
	int end;
	int cha;
};
jihe str[1000];
bool cmp(jihe a, jihe b) {
	return a.first < b.first;
}
int main() {
	int n;
	cin >> n;
	while (n--) {
		int flag = 1;
		int c;
		cin >> c;
		for (int y = 0; y < c; y++) {
			cin >> str[y].first >> str[y].end;
			str[y].cha = str[y].end - str[y].first;
		}
		sort(str, str + c, cmp);
		int max = str[0].cha;
		for (int i = 1; i < c; i++) {
			if (str[i].cha > max) {
				max = str[i].cha;
			}
		}

		for (int i = 0; i < c-1; i++) {
			if (str[i].first + max > str[i + 1].first) {
				flag = 0;
				break;
			}
		}
		if (flag == 1) {
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
	return 0;
}