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