二分查找or折半查找

 package com.gxf.search;

 /**
  * 测试折半查找or二分查找
  * @author xiangfei
  *
  */
 public class BiSearch {

     /**
      * 非递归实现,从第1个元素开始查找
      * @param array
      * @param k
      * @return 0 查找失败
      */
     public int biSearch(int array[], int k){
         int low = 1;
         int high = array.length - 1;

         while(low <= high){
             int mid = (low + high) / 2;
             if(k == array[mid]){
                 return mid;
             }
             if(k > array[mid]){
                 low = mid + 1;
             }
             else{
                 high = mid - 1;
             }
         }
         return 0;
     }

     /**
      * 递归实现
      * @param array
      * @param k
      * @param l
      * @param h
      * @return
      */
     public int biSearch(int array[], int k, int l, int h){
         if(l > h){
             return 0 ;
         }
         if(k == array[(l + h) / 2])
             return (l + h) / 2;
         else if(k > array[(l + h) / 2]){
             return biSearch(array, k, (l + h) / 2 + 1, h);
         }
         else{
             return biSearch(array, k, l, (l + h) / 2 - 1);
         }
     }

     public static void main(String[] args) {
         BiSearch biSearch = new BiSearch();
         int array[] = {0,1,3,4,5,6,7};
         System.out.println(biSearch.biSearch(array, 5));
         System.out.println(biSearch.biSearch(array, 5, 1, array.length - 1));

     }

 }