public static void reverse(int[] arr, int from, int to){
		int iters=0;
		if(from>to){
			iters=((arr.length-from)+to+1)/2;
		} else {
			iters=(to-from+1)/2;
		}
		
		while(iters>0){
			swap(arr,from,to);
			iters--;
			if(++from>=arr.length){ from=0; }
			if(--to<0){ to=arr.length-1; }
		}
	}