public static void quickSort(long[] a,int begin, int end){
		int left = begin;
		int right = end;
		long key = a[left];
		while(left < right){
			while(left < right && a[right] >= key)
				right--;
			if(left < right)
				a[left] = a[right];
			while(left < right && a[left] < key)
				left++;
			if(left < right)
				a[right] = a[left];
		}
		a[left] = key;
		if(left - begin > 1)
			quickSort(a,begin,left - 1);
		if(end - right > 1)
			quickSort(a,right + 1,end);
	}