View Code of Problem 6

#include<stdio.h>
int main(){
	int i,j,t,n,juli,h,flag;
	int a[1000],b[1000];

	scanf("%d",&t);	
	while(t--)	
	{
		flag=1;
		scanf("%d",&n);
		for(i=0;i<n;i++)
			scanf("%d%d",&a[i],&b[i]);
		for(i=0;i<n;i++)
			for(j=i;j<n;j++)
				if(a[i]>a[j])
				{
					h=a[i];
					a[i]=a[j];
					a[j]=h;
					h=b[i];
					b[i]=b[j];
					b[j]=h;
				}
				
		juli=b[0]-a[0];
		for(i=1;i<n;i++)
			if(a[i-1]+juli<=a[i] && a[i-1]+juli>=b[i-1] && a[i-1]+2*juli>=b[i])
				continue;
			else
			{
				flag=0;
				break;
			}
		
		if(t>0)
		{
		   if(flag==0)
			 printf("NO\n");
		   else
			   printf("YES\n");
		}
		else
		{
		   if(flag==0)
			 printf("NO");
		   else
			   printf("YES");
		}	
	}
  return 0;	
}