Transform array to hash map
Last updated: May 1, 2026
Quick Overview
Given an array of key-value pairs, transform it into a hash map where each key maps to its corresponding value. The output should be a hash map that accurately represents the relationships defined by the input array. If a key appears multiple times, the last value should be retained in the hash map.
ServiceNow
May 1, 202632
10
505 solved
Given an array of key-value pairs, transform it into a hash map where each key maps to its corresponding value. The output should be a hash map that accurately represents the relationships defined by the input array. If a key appears multiple times, the last value should be retained in the hash map.
This coding problem is frequently asked during Phone Screen at ServiceNow. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. ServiceNow expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- Can you solve this in a single pass?
- How would you parallelize this solution?
- Can you optimize the space complexity of your solution?
- What if the input doesn't fit in memory?
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Problem Analysis
In this problem, we need to transform an array of key-value pairs into a hash map (or dictionary in Python) where each key maps to its corresponding value. The challenge includes handling duplicate ke...
Approach
- Initialize an empty hash map (dictionary) to store our key-value pairs.
- Iterate through each pair in the input array:
- For each key-value pair, insert the key into the hash map with its corr...
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