简单算法--二分搜索

//二分搜索

 public int biSearch(int key,int[] intArray){

  

  int low = 0;

  int high = intArray.length-1;

  if(intArray[high] < key || intArray[low] > key) 

  { 

     System.out.println("This number is not in the range"); 

     return -1; 

  } 

  int middle = (low + high)/2 ;

  while(high>=low){

   if(intArray[middle] == key){

    System.out.println("find it");

    return middle;

   }else if(intArray[middle] < key){

    low = middle +1;

   }else{

    high = middle -1;

   }

   middle = (low + high)/2 ;

  }

  return -1;

 }