View Code of Problem 6

#include<iostream>

using namespace std;

int main()
{
	int T, n;
	cin >> T;
	if(T == 0)
	{
		return 0;
	}
	while (T--)
	{
		cin >> n;
		if(n == 0)
		{
			return 0;
		}
		int flag = 1;
		int l, r;
		cin >> l;
		cin >> r;
		int temp = r - l;
		while (--n)
		{
			cin >> l;
			cin >> r;
			int out = r - 1;
			if (out != temp)
			{
				flag = 0;
			}
		}
		if (flag == 0)
		{
			cout << "NO\n";
		}
		else
		{
			cout << "YES\n";
		}
	}
	return 0;
}