Uber Online Assessment SDE2/SDE3

Today, I completed the Uber Online Assessment for an SDE-2/SDE-3 role.

The assessment was conducted on HackerRank under strict proctoring (camera monitored) and consisted of 2 problems to be solved in 90 minutes.

Problem 1: Given a permutation of size n, we needed to construct a binary string of length n. For each k (1 ≤ k ≤ n), determine whether k is “balanced”.

A value k is considered balanced if there exists a subarray [l, r] such that the elements in that subarray form a permutation of numbers from 1 to k.

Constraints: 1 ≤ n ≤ 2 × 10^5

Examples: Input: [1, 3, 2, 4] Output: "1011"

Input: [3, 1, 2, 4] Output: "1111"

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Problem 2: We are given n plates placed on a 2D plane with coordinates defined by arrays x and y.

Two plates can be collected together if:

• They lie in the same row (same x) or same column (same y), and
• Their distance is ≤ d

The goal is to determine the minimum time required to collect all plates, where collecting one plate allows collecting all plates connected to it under these rules.

Constraints: 1 ≤ n ≤ 10^5 0 ≤ d ≤ 10^9 0 ≤ x[i], y[i] ≤ 10^9

Example: n = 3, d = 1 x = [0, 2, 1] y = [0, 1, 2] Output: 3

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Overall, the assessment focused heavily on efficient data structures and problem-solving under constraints (O(n log n) / O(n) solutions).

It was a great experience working through these problems.

I am able to solve both problems.