Find True-to-False Transition Index
Given a boolean array where the first element is always true and the last element is always false, find and return any index i such that arr[i] is true and arr[i+1] is false. Your solution must run in O(log n) time and O(1) space.
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Early May, 2026
Junior
You are given a boolean array arr of length n (where n >= 2). The array is guaranteed to follow two specific conditions: 1. The first element is always true (arr[0] == true). 2. The last element is always false (arr[n-1] == false). The values between the first and last elements can appear in any order. Your task is to find and return any index i such that arr[i] is true and arr[i+1] is false. Constraints * Time Complexity: O(log n) * Space Complexity: O(1) * The array may contain multiple such transitions; returning the index of any valid transition is acceptable. Example 1 Input: arr = [true, false, false, false, false, true, true, false] Output: 0 or 6 Example 2 Input: arr = [true, true, true, false] Output: 2 Do you need the O(log n) solution written out in a specific programming language to go with this statement?
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