Description
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.
Solution
Python3
class Solution:
def search(self, nums: List[int], target: int) -> int:
n = len(nums)
left, right = 0, n - 1
while left < right:
mid = left + (right - left) // 2
if nums[mid] >= target:
right = mid
else:
left = mid + 1
return left if nums[left] == target else -1