public static int patition(int[] src,int start,int end){
		if(src == null || start > end){
			return -1;
		}
		int index = (start + end) / 2;
		swap(src,index,end);
		int small = -1;
		for(int i=0;i< src.length;i++){
			if(src[i] < src[end]){
				small++;
				swap(src,i,small);
			}
		}
		small++;
		swap(src,small,end);
		return small;
	}