Count friend requests based on age rules
Company: Bloomberg
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
## Problem
You are given an array `ages`, where `ages[i]` is the age of the `i`-th person. A person of age **A** will send a **friend request** to a person of age **B** if all conditions hold:
1. \(B > 0.5 \times A + 7\)
2. \(B \le A\)
Each request is **directed** (A→B). A person cannot send a request to themselves.
Return the **total number of friend requests** that will be sent.
## Input
- `ages`: integer array
## Output
- An integer: total number of directed friend requests.
## Constraints (you may assume typical interview bounds)
- \(1 \le n \le 2\times 10^4\)
- \(1 \le ages[i] \le 120\)
## Examples
1) `ages = [16, 16]`
- Each 16-year-old can request the other (since \(16 > 0.5\cdot16 + 7 = 15\) and \(16 \le 16\))
- Total = 2
2) `ages = [20, 30, 100, 110, 120]`
- Compute total directed requests that satisfy the rules.
Quick Answer: This question evaluates algorithmic problem-solving skills involving array processing, counting and combinatorics under conditional constraints and frequency handling.
Count ordered friend requests between people using the standard age 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.
Hints
- Start with a direct data structure representation.
- Handle edge cases before the main loop.