2分排序 例子

二分排序 例子
题目：一个有序的数组，里面是一万个整数。随机切分两部分，然后互换位置。求一个数的位置

for example:

int[] numbers = {92, 99,101,102,104,105,109,110,115,166,300,400,500, 1, 12, 13, 34, 35, 56, 57};

public class Test
{

    /**
     * @param args
     */
    public static void main(String[] args)
    {
 
        
  
        int[] numbers = {92, 99,101,102,104,105,109,110,115,166,300,400,500, 1, 12, 13, 34, 35, 56, 57};
//        System.out.println(Test.getPosition(numbers, 0));
//        System.out.println(Test.getPosition(numbers, 1));
//        System.out.println(Test.getPosition(numbers, 11));
//        System.out.println(Test.getPosition(numbers, 13));
//        System.out.println(Test.getPosition(numbers, 33));
//        System.out.println(Test.getPosition(numbers, 35));
//        System.out.println(Test.getPosition(numbers, 43));
//        System.out.println(Test.getPosition(numbers, 57));
//        System.out.println(Test.getPosition(numbers, 66));
//        System.out.println(Test.getPosition(numbers, 92));
//        System.out.println(Test.getPosition(numbers, 97));
//        System.out.println(Test.getPosition(numbers, 99));
//        System.out.println(Test.getPosition(numbers, 100));
        System.out.println(Test.getPosition(numbers, 400));
      

    } 
    
    private static int getPosition(int[] numbers, int number)
    {
        int seperator = numbers[0];
        int low = 0;
        int high = numbers.length - 1;
        
        while(low < high)
        {
            int mid = (low + high)/2;
            int midNumber = numbers[mid];
            if(midNumber == number)
            {
                return mid;
            }

            if(number == seperator)
            {
                return low;
            }

            if(number > seperator)
            {
                if(number > midNumber&& midNumber >= seperator)
                {
                    low = mid + 1;
                }else
                {
                    high = mid - 1;
                }
            }else 
            {
                if(number < midNumber&& midNumber < seperator)
                {
                    high = mid - 1;
                }else
                {
                    low = mid + 1;
                }
            }
        }
        
        if(high >= 0&& numbers[high] == number)
        {
            return high;
        }
        if(low < numbers.length&& numbers[low] == number)
        {
            return low;
        }
        return -1;
    }
 


    
   

   
}