Learning GoLang: Binary Search Algorithm

justyy (84)in #programming • 5 years ago

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

Binary Search Algorithm Implementation in GoLang

Using GoLang to search a number in an array of sorted numbers using Binary Search. The time complexity is O(LogN).

func search(nums []int, target int) int {
    var i, j = 0, len(nums) - 1
    for i <= j {
        var mid = i + (j - i) / 2
        if nums[mid] == target {
            return mid
        }
        if target > nums[mid] {
            i = mid + 1
        } else {
            j = mid - 1
        }
    }    
    return -1
}

See other Binary Search algorithms:

Reposted from Blog