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, 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 at index 4.
Example 2
Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 not in nums.
1 <= nums.length <= 10^4All integers in nums are unique.-10^4 < nums[i], target < 10^4Left + (right - left) / 2 to avoid integer overflow.
public int search(int[] nums, int target) {
int left = 0, right = nums.length - 1;
while (left <= right) {
int mid = left + (right - left) / 2; // avoids overflow
if (nums[mid] == target) return mid;
else if (nums[mid] < target) left = mid + 1;
else right = mid - 1;
}
return -1;
}Time: O(log n) · Space: O(1)