Count ordered fragment pairs forming a password
Company: Capital One
Role: Machine Learning Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Take-home Project
You are given:
- A target string `password`.
- A list of `N` string fragments `fragments[0..N-1]` (fragments may repeat).
Count the number of **ordered pairs of distinct indices** `(i, j)` such that:
`fragments[i] + fragments[j] == password`
Notes:
- “Ordered” means `(i, j)` and `(j, i)` are counted separately when both satisfy the condition.
- Indices must be distinct (`i != j`).
**Input:** `password`, `fragments`.
**Output:** an integer count (potentially large; specify/assume 64-bit).
State any constraints you assume and handle duplicates correctly.
Quick Answer: This question evaluates proficiency with string manipulation, handling duplicate fragments, and combinatorial reasoning about ordered index pairs that concatenate to a target, reflecting algorithmic problem-solving and correctness under index distinctness constraints.
