public static int patition(int[] array,int start,int end){
		if(array == null || start > end){
			return -1;
		}
		int index = (start+end )/2;
		swap(array,index,end);
		int small = start - 1;
		for(int i = start;i < end ;i++){
			if(array[i] < array[end]){
				small ++;
				swap(array,small,i);
			}
		}
		small ++;
		swap(array,small,end);
		return small;
		
	}