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Problem

Binary Search

Easy
  • binary-search

nums is sorted in ascending order and has no repeated values. Return the index of target in it, or -1 if target is not there.

A scan from the left is too slow. The search has to take O(log n) time.

Example 1
Input
nums = [3, 8, 14, 21, 30, 47, 52], target = 30
Output
4
Explanation

30 is stored at index 4.

Example 2
Input
nums = [3, 8, 14, 21, 30, 47, 52], target = 25
Output
-1
Explanation

25 would sit between 21 and 30, but it is not in the array.

Example 3
Input
nums = [], target = 4
Output
-1
Explanation

an empty array holds nothing to find.

Constraints:

  • 0 <= nums.length <= 10^5
  • -10^9 <= nums[i], target <= 10^9
  • nums is sorted in ascending order and its values are distinct

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