二分查找

    public static int search(int[] array,int key){
        int low=0;
        int high=array.length-1;
        int middle=(low+high)/2;
        while(true){
            if(key==array[middle]){
                return middle;
            }else if (low>high){
                break;
            }
            if(key>array[middle]){
                low= middle + 1;
                middle=(low+high)/2;
            }else if(key<array[middle]){
                high= middle - 1;
                middle=(low+high)/2;
            }
        }
        return 0;
    }