704. 二分查找

https://leetcode-cn.com/problems/binary-search/

class Solution {
    public int search(int[] nums, int target) {
        return search(nums,target,0,nums.length - 1);
    }
    private int search(int[] arr,int target,int low,int high){
        if(low > high) return -1;

        int mid = (low + high) >> 1;

        if(arr[mid] > target){
            return search(arr,target,low,mid - 1);
        }else if(arr[mid] < target){
            return search(arr,target,mid+1,high); 
        }else{
            return mid;
        }
    }
}