Solve three algorithmic OA tasks
Algorithmic Challenges
This problem consists of three independent algorithmic tasks. Candidates are expected to provide efficient and correct solutions for each.
Task 1: Odd-Frequency String Generation
Given an integer N within the range [1, 200000], design an algorithm that generates and returns any string of length N. This string must consist solely of lowercase English letters (a-z), and every letter that appears in the string must occur an odd number of times.
Task 2: Minimum Difference with Minimal Swaps
You are provided with two digit strings, S and T, of equal length N (where N can be up to 100000). These strings contain only digits and do not have leading zeros. You have the option to choose a subset of indices i and swap the characters S[i] and T[i] at each chosen index. The objective is to find a set of swaps that minimizes the absolute difference |int(S) − int(T)|. Among all swap choices that achieve this minimum difference, you must return the minimum number of swaps required.
For example:
If S = "29162" and T = "10524", the expected output is 2.
Task 3: Two-Choice Slot Assignment
You are given two arrays, A and B, both of length N. For each index k (representing a patient), A[k] and B[k] represent two distinct slot choices, where 1 ≤ A[k], B[k] ≤ S and A[k] ≠ B[k]. S is an integer representing the total number of available slots, ranging from 2 to 100000. Determine if it is possible to assign every patient k to exactly one of their two choices (A[k] or B[k]) such that no two patients are assigned to the same slot. Return true if such an assignment exists, otherwise false.
AI interview prep
Core dilemma
Balancing algorithmic optimality (time/space) with robust edge case handling and clear, justifiable design choices across diverse problem types, especially under given constraints.
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
Solve three algorithmic OA tasks
Algorithmic Challenges
This problem consists of three independent algorithmic tasks. Candidates are expected to provide efficient and correct solutions for each.
Task 1: Odd-Frequency String Generation
Given an integer N within the range [1, 200000], design an algorithm that generates and returns any string of length N. This string must consist solely of lowercase English letters (a-z), and every letter that appears in the string must occur an odd number of times.
Task 2: Minimum Difference with Minimal Swaps
You are provided with two digit strings, S and T, of equal length N (where N can be up to 100000). These strings contain only digits and do not have leading zeros. You have the option to choose a subset of indices i and swap the characters S[i] and T[i] at each chosen index. The objective is to find a set of swaps that minimizes the absolute difference |int(S) − int(T)|. Among all swap choices that achieve this minimum difference, you must return the minimum number of swaps required.
For example:
If S = "29162" and T = "10524", the expected output is 2.
Task 3: Two-Choice Slot Assignment
You are given two arrays, A and B, both of length N. For each index k (representing a patient), A[k] and B[k] represent two distinct slot choices, where 1 ≤ A[k], B[k] ≤ S and A[k] ≠ B[k]. S is an integer representing the total number of available slots, ranging from 2 to 100000. Determine if it is possible to assign every patient k to exactly one of their two choices (A[k] or B[k]) such that no two patients are assigned to the same slot. Return true if such an assignment exists, otherwise false.