View Code of Problem 6

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		int t,n;
		int max;
		Scanner in = new Scanner(System.in);
		t=in.nextInt();
		while(t--!=0){
			n=in.nextInt();
			int l[] = new int[n];
			int r[] = new int[n];
			for(int i=0;i<n;i++){
				l[i]=in.nextInt();
				r[i]=in.nextInt();
				
				
			}
			 max=r[0]-l[0];
			 int i;
			for( i=1;i<n;i++){
				if((r[i]-l[i])>max)
					max=r[i]-l[i];
			}
			for( i=0;i<n-1;i++){
				
				if(l[i]+max>l[i+1]){
					System.out.println("NO");
					break;
					}
				
			}
				if(i==n-1)
					System.out.println("YES");
				
			
			
		}
	}
	
}