Google·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say

Apr 2026

Summary

Google SWE coding round with a sequence/keyboard problem that looked deceptively simple but had a bunch of underspecified edge cases that you're supposed to catch and ask about.

Questions Asked (1)

Given a sequence of integer positions on an infinite keyboard, find the minimum number of times you need to move your hand to play the entire sequence. Follow-up: each time you move your hand, output the segment you just finished playing, and also output the final segment at the end.

Algorithms & Data StructuresAdaptability & Ambiguity

Author's notes

The problem sounds like a basic greedy grouping thing but the definition of 'hand position' is intentionally vague.

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AI HintsAI Generated

Suggested Approach

Clarify the problem constraints and define what constitutes a 'move' (e.g., hand repositioning to a new starting position). Then, model the sequence as a series of segments where each move resets the hand position, and the goal is to minimize the number of moves by optimally grouping consecutive positions that can be played without moving. For the follow-up, track the start and end indices of each segment and output them as you go, ensuring the final segment is also output.

Pro tip: Demonstrate adaptability by discussing edge cases (e.g., empty sequence, single element) and asking clarifying questions about the keyboard layout and movement rules. This shows you think about ambiguity and real-world constraints, which is crucial at Google.

1. Clarify the problem

Ask questions to understand the keyboard layout, what constitutes a move, and whether the hand can play any position without moving if it's already there. Confirm the output format for the follow-up.

2. Define the greedy strategy

Explain that to minimize moves, you should play as many consecutive positions as possible without moving, and only move when the next position is not reachable from the current hand position. This leads to a greedy segmentation.

3. Design the algorithm

Iterate through the sequence, maintaining the start of the current segment. When a move is required (i.e., the next position cannot be played from the current hand position), increment the move count and record the segment. At the end, record the final segment.

4. Handle the follow-up

Modify the algorithm to output each segment (as a subarray or indices) when a move occurs, and also output the final segment after the loop. Ensure the output format matches the requirement.

5. Analyze complexity and edge cases

State that the solution is O(n) time and O(1) extra space (if only counting moves) or O(n) for storing segments. Discuss edge cases like empty input, single element, and all elements requiring moves.

Key Points to Mention

Greedy approach: always play the longest possible segment without moving.
Definition of a move: repositioning the hand to a new starting position.
Tracking segments using start and end indices.
Outputting segments during iteration and after the loop.
Time and space complexity analysis.
Edge cases: empty sequence, single element, and sequences where every element requires a move.

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