View Code of Problem 6

import java.util.Scanner;

public class Main {
    static Scanner in = new Scanner(System.in);

    public static void main(String[] args) {
        int T=in.nextInt();
        for (int i = 0; i < T; i++) {
            int n = in.nextInt();
            int [][] a=new int[n][2];
            int maxStep=0;
            for (int j = 0; j < n; j++) {
                a[j][0] = in.nextInt();
                a[j][1] = in.nextInt();
                if (a[j][1]-a[j][0]>maxStep){
                    maxStep=a[j][1]-a[j][0];
                }
            }
            //mock
            int pos=a[0][0];
            boolean flag=true;
            for (int j = 0; j < n-1; j++) {
                pos=pos+maxStep;
                if (pos <= a[j + 1][0]) {

                } else {
                    flag=false;
                }
            }
            if (flag) {
                System.out.println("YES");
            } else {
                System.out.println("NO");
            }
        }
    }

}