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This question evaluates algorithmic skills in counting, frequency analysis, constraint-based pair counting, and stream-oriented tokenization and ranking, and is categorized under Coding & Algorithms for software engineer roles.

  • medium
  • Meta
  • Coding & Algorithms
  • Software Engineer

Solve counting and frequency coding tasks

Company: Meta

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Technical Screen

You are given two separate coding tasks. ## Task 1: Count valid “friend requests” You are given an array `ages[]` of integers representing users’ ages. A user of age `A` can send a friend request to a user of age `B` **iff** all conditions hold: - `B <= 0.5 * A + 7` is **false** (i.e., `B` must be strictly greater than `0.5*A + 7`) - `B > A` is **false** (i.e., `B <= A`) - If `B > 100`, then `A >= 100` (i.e., users under 100 cannot request users over 100) Each ordered pair `(i, j)` with `i != j` counts as one request if `ages[i]` can request `ages[j]`. **Output:** return the total number of valid friend requests. **Constraints (typical interview scale):** - `1 <= n <= 2e4` - `1 <= ages[i] <= 120` ## Task 2: Top-N frequent words from a text source You are given an input text source (conceptually a file/stream) containing words separated by whitespace and/or punctuation. **Goal:** return the `N` most frequent words along with their counts. **Requirements/clarifications:** - Define how you tokenize words (e.g., case-insensitive, strip punctuation). - If multiple words have the same frequency, define a deterministic tie-break (e.g., lexicographic order). - The input may be too large to fit into memory as a single string; assume you can read line-by-line. **Input:** a stream of text and an integer `N`. **Output:** a list of up to `N` `(word, count)` pairs sorted by decreasing count (and tie-break rule). **Constraints (typical interview scale):** - Total tokens can be large (e.g., millions) - `1 <= N <= number_of_distinct_words`

Quick Answer: This question evaluates algorithmic skills in counting, frequency analysis, constraint-based pair counting, and stream-oriented tokenization and ranking, and is categorized under Coding & Algorithms for software engineer roles.

Friend Requests by Age

Count ordered friend requests using the age eligibility rules.

Constraints

  • Inputs are provided as Python literals compatible with the function signature.
  • Return a deterministic value exactly matching the requested output.

Examples

Input: ([16, 16],)

Expected Output: 2

Explanation: Two reciprocal requests.

Input: ([16, 17, 18],)

Expected Output: 2

Explanation: Mixed ages.

Input: ([20, 30, 100, 110, 120],)

Expected Output: 3

Explanation: Over-100 rule.

Hints

  1. Start with a direct data structure representation.
  2. Handle edge cases before the main loop.

Top N Frequent Words

Return the n most frequent words, sorting ties lexicographically ascending.

Constraints

  • Inputs are provided as Python literals compatible with the function signature.
  • Return a deterministic value exactly matching the requested output.

Examples

Input: (['i', 'love', 'leetcode', 'i', 'love', 'coding'], 2)

Expected Output: ['i', 'love']

Explanation: Frequency tie.

Input: (['the', 'day', 'is', 'sunny', 'the', 'the', 'the', 'sunny', 'is', 'is'], 4)

Expected Output: ['the', 'is', 'sunny', 'day']

Explanation: Classic example.

Input: (['a', 'b'], 5)

Expected Output: ['a', 'b']

Explanation: n exceeds distinct words.

Hints

  1. Start with a direct data structure representation.
  2. Handle edge cases before the main loop.
Last updated: Jun 27, 2026

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