View Code of Problem 6

#include <stdio.h>
void main(){
	int T;
	scanf("%d",&T);
	while(T--){
		int n,k;
		scanf("%d",&n);
		int a[2*n],i=0;
		k=n;
		while(k--){
			scanf("%d %d",&a[i],&a[i+1]);
			i=i+2;
		}
		int step;
		step=a[1]-a[0];
		for(i=0;i<=2*n-2;i=i+2){
			if(a[i+1]-a[i]!=step){
				printf("NO\n");
				break;
			} 
			if((i+2)<2*n&&(a[i+2]-a[i+1])%step!=0){
				printf("NO\n");
				break;
			} 
		}
		if(i>2*n-2) printf("YES\n");
	}
}