题解 | #二分查找-I#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型一维数组 
     * @param target int整型 
     * @return int整型
     */
    public int search (int[] nums, int target) {
        // write code here
        if(nums == null || nums.length == 0) {
            return -1;
        }
        return find(nums, target, 0, nums.length);        
    }

    public int find(int[] nums, int target, int start, int end) {        
        int middle = start + (end - start) / 2;
        if(nums[middle] == target) {
            return middle;
        }
        if((end - start) <= 1) {
            return -1;    
        }
        if(nums[middle] > target) {
            return find(nums, target, start, middle);
        }
        if(nums[middle] < target) {
            return find(nums, target, middle, end);
        }
        
        return -1;

    }
}