View Code of Problem 6

#include<stdio.h>
#include<stdlib.h>

int main()
{
	int t,n;
	int left;int right;
	int len;
	int pos=0;
	int flag=1;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d",&n);
		for(int i=0;i<n;i++)
		{
			scanf("%d %d",&left,&right);
			if(left>right)
				return -1;
			if(i==0)
			{
				len=right-left;
				pos=right;
			}else{
				while(pos<right)
				{
					if(pos<left)
					{
						int time=(left-pos)/len;
						pos=pos+time*len;
					}
					pos+=len;
					if(pos>left&&pos<right)
					{
						flag=0;
						break;
					}
				}
			}
		}
		if(flag)
			printf("YES\n");
		else
			printf("NO\n");
	}
	return 0;
}