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));

    }

}