Jerry.ai·Software Engineer·Online Assessment (OA)·Intermediate

IntermediatePrefer not to say

May 2026

Summary

OA for a software engineer role at Jerry.ai. One string manipulation problem that seemed manageable until it wasn't.

Questions Asked (1)

Given two strings, determine if one can be transformed into the other using exactly one operation (add a character, remove a character, replace a character, or move a character to a different position). If yes, output which operation was used.

Algorithms & Data Structures

Author's notes

The add and replace cases weren't too bad to reason through.

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AI HintsAI Generated

Suggested Approach

First, clarify the operation definitions and edge cases, especially the 'move' operation, which is ambiguous. Then, propose a solution that checks each operation type systematically, using length differences to narrow down possibilities, and handle the move operation by checking if the strings can be made equal by relocating one character.

Pro tip: Demonstrate awareness of the ambiguity in 'move' and suggest a precise definition (e.g., remove a character and insert it elsewhere) to show attention to detail. Also, discuss time/space complexity and potential optimizations.

1. Clarify requirements and edge cases

Ask the interviewer to define 'move' precisely and confirm if operations are case-sensitive, if strings can be empty, and if the operation must be exactly one (not zero).

2. Analyze length differences

Use length comparison to quickly eliminate impossible cases: if lengths differ by more than 1, only 'move' (which preserves length) or 'replace' (same length) might apply, but 'add'/'remove' require length difference of 1.

3. Check simple operations (add, remove, replace)

For add/remove, verify if the longer string can be obtained by inserting/deleting one character from the shorter. For replace, check if exactly one character differs at the same position.

4. Check move operation

If lengths are equal and replace fails, check if moving one character (remove and insert elsewhere) can transform one string into the other. This can be done by finding the first mismatch and verifying if the remaining substrings match after accounting for the moved character.

5. Return result and discuss complexity

Return the operation if found, else indicate no single operation works. Analyze time complexity (likely O(n)) and space complexity (O(1) or O(n) depending on implementation).

Key Points to Mention

Edge cases: empty strings, identical strings (zero operations), strings differing by more than one operation.
Length-based filtering: add/remove require length difference of 1; replace and move require equal lengths.
Efficient checking for add/remove: use two pointers to find the single mismatch and verify the rest matches.
Move operation: define as removing a character and inserting it at a different position; check by finding the first mismatch and testing if the remaining substrings align after shifting.
Time and space complexity: aim for O(n) time and O(1) extra space.
Handling multiple possible operations: if more than one operation could work, clarify with interviewer which to return or if any is acceptable.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.