Binary Search - Implementation

function binarySearch(arr, target):
    left = 0
    right = arr.length - 1
    while left <= right:
        mid = (left + right) // 2
        if arr[mid] == target:
            return mid
        else if arr[mid] < target:
            left = mid + 1
        else:
            right = mid - 1
    return -1

Time: O(log n). Space: O(1). Each iteration halves the range.