java 二分法查找

public static int halfSearch(int a[],int key){
	int low = 0, hight = a.length - 1;
	while(low <= hight){
	    int mid = (low + hight)/2;
		if (a[mid] == key)  
			return mid;
		else if (a[mid] < key) 
			low = mid + 1;
		else
			hight = mid + 1;
	}
	return -1;
}