Binary Search

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. 

Example 1:

Input: nums = [-1,0,3,5,9,12], target = 9

Output: 4

Example 2:

Input: nums = [-1,0,3,5,9,12], target = 2

Output: -1

 

Constraints:

• 1 <= nums.length <= 104
• -104 < nums[i], target < 104

All the integers in nums are unique.

二分法搜索

给你一个按升序排列好的整数数组nums，和一个整数 target ，下一个函数去nums中寻找target，如果 target存在，返回它的下标，否则返回-1.

例子1

输入：nums = [-1,0,3,5,9,12], target = 9

输出：-1

例子2

输入：nums = [-1,0,3,5,9,12],target=2

输出: -1

限制

Nums 长度<10000

-10000<nums[i],target<10000

Nums中整数都不重复