View Code of Problem 6

#include <stdio.h>
#include <string.h>
#include <math.h>
int main()
{
	int t;
	int l[50000], r[50000];
	scanf("%d", &t);
	while (t--)
	{
		int n;
		scanf("%d", &n);
		for (int i = 0; i < n; i++)
			scanf("%d%d", &l[i], &r[i]);
		int max=r[0]-l[0];
		for (int i = 1; i < n; i++)
			if (r[i] - l[i] > max)
				max = r[i] - l[i];
		int flag = 0;
		for (int i = 0; i < n - 1; i++)
			if (l[i] + max > l[i + 1])
			{
				flag = 1;
				break;
			}
		if (flag == 1)
			printf("NO\n");
		else
			printf("YES\n");
	}
	return 0;
}