Increasing Paths 2
Reported by candidates from Hudson River Trading's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
Hudson River Trading hit you with a graph problem in August 2024 and didn't include the full text. Increasing Paths 2 is a follow-up variant, which means it's probably harder than the original and tests whether you can adapt a solution under pressure. You're looking at a depth-first search or dynamic programming pattern, likely with memoization to avoid recomputing paths. This is exactly the kind of problem where StealthCoder acts as your safety net if you freeze on the structure during the live OA.
Pattern and pitfall
Increasing Paths 2 almost certainly asks you to count or find paths in a graph where each step increases in value (or follows some ordering rule). The trick is recognizing that naive recursion will timeout, so you need memoization to cache results from each node. You explore from a node, recurse to its neighbors that satisfy the constraint, and store the result so you never recompute it. The variant twist in a '2' problem usually means more complex state (2D grid, weighted edges, or multi-condition constraints). When you blank on whether to use DFS or DP during your OA, StealthCoder will show you the pattern immediately.
StealthCoder is the hedge for the one pattern you didn't drill. It runs invisibly during the screen share.
You can drill Increasing Paths 2 cold, or you can hedge it. StealthCoder runs invisibly during screen share and surfaces a working solution in under 2 seconds. The proctor sees the IDE. They don't see what's behind it. If you're reading this with an OA window open, you're who this was built for.
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Hudson River Trading reuses patterns across OAs. If you're reading this with an OA window open, you're who this was built for. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Increasing Paths 2 FAQ
Is this a graph problem or a grid problem?+
The title 'Paths' suggests you're moving through a structure. Without the full text it's hard to be certain, but Hudson River Trading favors both. If it's a grid, treat it as an implicit graph. Memoization works either way.
What's the common pitfall candidates miss?+
Writing recursive DFS without memoization, leading to exponential time. Also forgetting to handle the base case (when you can't move further). Test with small inputs where you count all valid paths by hand first.
Is this still asked at HRT?+
Yes. Graph and path-counting problems are core to their coding bar. Expect variants on this theme. The '2' suffix suggests it's an established problem they rotate through.
How do I prepare in 48 hours?+
Solve the original 'Increasing Paths' on LeetCode (Number of Increasing Paths in a Matrix). Then write memoized DFS from scratch twice. Trace through one example by hand. That covers the core pattern.
What if I don't know if it's a directed or undirected graph?+
The word 'Increasing' implies direction and order. Treat it as directed unless the problem says otherwise. An 'increasing' constraint naturally prevents cycles, which simplifies memoization.