Assessment Overview
The ByteDance OA is a 90-minute coding challenge featuring three algorithmic and mathematical problems. It tests your ability to solve complex problems efficiently with clean, logical code.
Question 1: Longest Subsequence with Bounded Adjacent Differences
Task
Given an integer list, find the maximum length of a subsequence where the absolute difference between consecutive elements is ≤ k.
Example
Input: nums = [1, 3, 5, 7, 9], k = 2
Output: 5
Explanation: The entire list forms a valid subsequence since each adjacent pair differs by at most 2.
Question 2: Unique Paths to Bottom Row with Column Constraints
Task
A robot starts at the top-left corner (0, 0) of a grid and can move down, left, or right (but not up). For n steps, count the distinct paths that reach the bottom row, with each step landing in a new column.
Example
Input: n = 3
Output: 2
Explanation: The valid paths are (down → right → down) and (down → left → down), each ensuring unique columns in every step.
Question 3: Largest Rectangle in Histogram
Task
Given a list of bar heights in a histogram (each with width 1), compute the maximum rectangular area that can be formed.
Example
Input: heights = [2, 1, 5, 6, 2, 3]
Output: 10
Explanation: The bars of heights 5 and 6 form a rectangle of height 5 (or 6) and width 2, yielding an area of 10.
Final Thoughts
The ByteDance OA demands a mix of problem-solving creativity and algorithmic efficiency. Mastering these high-frequency questions-along with their Mastering these high-frequency questions-along with their underlying patterns like dynamic programming for subsequences or stack-based approaches for histograms-will sharpen your readiness.
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