# [Solved] 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. ## Question

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`.

You must write an algorithm with `O(log n)` runtime complexity.

Example 1:

```Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4
```

Example 2:

```Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 does not exist in nums so return -1
```

Constraints:

• `1 <= nums.length <= 104`
• `-104 < nums[i], target < 104`
• All the integers in `nums` are unique.
• `nums` is sorted in ascending order.

## Python Solution

```class Solution:
def search(self, nums: List[int], target: int) -> int:
l = 0
r = len(nums)-1

while l<=r:
m = l + (r-l)//2
if nums[m]>target:
r=m-1
elif nums[m]<target:
l=m+1
else:
return m
return -1```