Implement Hash Map with without recursion
Last updated: August 11, 2025
Quick Overview
Implement a hash map data structure that supports insertion, deletion, and lookup operations in average O(1) time complexity. Your implementation should handle collisions using chaining or open addressing. The input will consist of key-value pairs for insertion, keys for deletion and lookup, and the output should reflect the success or failure of these operations.
Salesforce
August 11, 2025265
4
274 solved
Implement a hash map data structure that supports insertion, deletion, and lookup operations in average O(1) time complexity. Your implementation should handle collisions using chaining or open addressing. The input will consist of key-value pairs for insertion, keys for deletion and lookup, and the output should reflect the success or failure of these operations.
This coding problem is frequently asked during Onsite at Salesforce. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Salesforce 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 optimize the space complexity of your solution?
- How would you modify your solution to handle streaming input?
- Can you solve this iteratively instead of recursively (or vice versa)?
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Practice DSA ProblemsSample Answer
Problem Analysis
To implement a hash map, we need to focus on an efficient way to store and retrieve key-value pairs. A hash map typically uses an array for storage and a hash function to compute an index for each key...
Approach
- Initialization: Create a class
HashMapwith an internal array (e.g., of size 1000) and initialize each index to an empty list for chaining. - Hash Function: Define a method to compute t...
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