Snowflake Interview Questions — Page 6

Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE interview with a coding round that was basically the Dutch National Flag problem dressed up in a different costume. The API-only constraint made it trickier than it looks on paper.

You're given a RecordCollection object with size(), getColor(i), and swap(i, j) as the only available operations. Each record has a color: 0 (Red), 1 (Green), or 2 (Blue). Sort the collection in place so all reds come first, then greens, then blues. Must run in O(n) time, O(1) space, single pass, no auxiliary arrays.

“The moment I saw the three-color constraint and single-pass requirement I knew it was the classic three-pointer partition problem.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake software engineer interview with a grid-based BFS problem. Pretty standard coding round but the problem had enough nuance to trip you up if you weren't careful about multi-source traversal.

Given an m x n grid containing desk cells, bathroom cells, and empty cells, find for each desk the shortest path distance to its nearest bathroom using only up/down/left/right moves. Return a matrix with those distances, or -1 for desks that can't reach any bathroom.

“My first instinct was to BFS from each desk individually and that works but it's slow if you have a lot of desks.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE coding round, just the one problem but it was a classic grid BFS that I kept overcomplicating in my head.

You have an m x n grid where cells are either walls (-1), gates (0), or empty rooms (INF). Fill every empty room with its shortest distance to any gate, in-place.

“I knew BFS was the right call but I started thinking about running BFS from each empty room separately, which is obviously wrong and I caught it maybe two minutes in.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE coding round with a tree problem that had a twist I didn't fully expect going in.

Given a binary tree, determine whether the value of the root node equals the average value of all nodes across every subtree.

“It's a tree averaging problem but the condition being on the root specifically threw me a bit.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE interview with two tree problems back to back, both built around the same unusual deletion rule where you promote children up instead of just removing the node. The warm-up felt manageable but the main problem had enough moving parts that I was scrambling by the end.

You have a rooted binary tree with unique node IDs and a list of nodes to delete. When you delete a node, its children get promoted to fill its spot under the deleted node's parent, preserving left/right positions where possible. After all deletions, how many levels does the resulting tree have? Also handle the case where the root itself gets deleted, which produces a forest, and return the max height across all resulting trees. What's the time and space complexity?
Using the same child-promotion deletion rule, given a rooted binary tree, a max number of deletions n, and a target height k, return all unique sets of node IDs whose deletion results in a tree of exactly height k using at most n deletions. Each set should be returned as a sorted list, with no duplicate sets in the output. Walk through your search and pruning strategy, argue correctness, and analyze complexity.

“The promotion rule is what makes this feel different from a standard delete question.”

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Snowflake·Software Engineer·Online Assessment (OA)

May 2026

Snowflake OA with a math-heavy twist. The problem looked like a grid question but really just needed you to spot the closed-form formula fast enough to not overthink it.

Given Q queries, each with a (rows, cols) pair, compute for each query the count of cells on or above the main diagonal of the smaller square sub-rectangle formed by those dimensions.

“The key move is realizing you only care about m = min(rows, cols) and then it collapses to m*(m+1)/2.”

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Snowflake·Software Engineer·Onsite - System Design / Architecture

May 2026

Snowflake system design round, one question about building a key-value store from scratch. Pretty focused session, they wanted to see how far you'd take the design before they had to prompt you.

Design an in-memory key-value store with put, get, and delete operations. How would you extend it to support TTL, snapshots, or transactions?

“I covered the basics pretty fast and then just sat there waiting for them to push me toward the extensions.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE interview that went pretty deep on trees. One main coding problem but they kept pulling the thread on it, so by the end it felt like four questions in a trench coat.

Given a binary tree (not necessarily a BST) and two node values u and v, return the list of node values representing the shortest path from u to v. If either node is missing, return an empty list. Your solution should run in O(n) time and O(h) extra space using LCA.
Provide both a recursive and an iterative implementation of the path-finding solution, and walk through the time and space complexity of each.
If you need to answer many path queries on the same tree, what preprocessing strategies would you use? Discuss parent pointer storage, Euler tour with RMQ for LCA, and binary lifting, including the trade-offs between preprocessing cost and per-query cost.
How does your solution handle edge cases: a node that doesn't exist in the tree, u equal to v, one node being an ancestor of the other, duplicate values, and very deep skewed trees where recursion might overflow the stack?

“I got the LCA idea pretty fast but fumbled on actually reconstructing the path.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE interview with two BFS problems back to back. Started manageable and got harder fast.

Find the shortest path on a number line where you can make specific allowed jumps from any position.
Extend the previous problem to a 2D grid with obstacles or variable move costs. Find the shortest path.

“BFS on a 1D structure feels almost too simple until you realize your visited set has to actually be right or you'll loop forever.”

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Snowflake·Software Engineer·Technical Phone Screen

May 2026

Snowflake SWE interview that went deep into graph algorithms pretty fast. The question looked like a clean CS problem on the surface but they really wanted to see if you understood the performance implications at scale, which is very on-brand for a data warehouse company.

Given a directed acyclic graph, compute the transitive closure so that for each node you know every other node reachable from it. Then discuss the trade-offs between doing a DFS from each node versus a topological-order propagation approach using bitsets.

“I started with the naive DFS-per-node answer because that's the obvious one and I figured I'd build from there.”

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