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
        int left = 0, right = nums.length-1;
        if (nums.length==0){
            return -1;
        }
        int mid= 0;
        int index;
        while (left <= right) {
            mid = (left + right) / 2;
            if (target < nums[mid]) {
                right = mid -1;

            } else if (target > nums[mid]) {
                left = mid + 1;
            } else {
                return mid;
            }
        }
        return -1;
    }
}

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 binary(int[] nums,int left,int right,int target){
        if (left>right){
            return -1;
        }
        int mid = (left+right)/2;
        if (target<nums[mid]){
            return binary(nums,left,mid-1,target);
        }else if(target>nums[mid]){
            return binary(nums,mid+1,right,target);
        }else{
            return mid;
        }
    }
    public int search (int[] nums, int target) {
        // write code here
        return binary(nums,0,nums.length-1,target);
    }
}