Binary Tree Tilt
A easy-tier problem at 64% community acceptance, tagged with Tree, Depth-First Search, Binary Tree. Reported in interviews at Indeed and 0 others.
Binary Tree Tilt is an easy tree problem that shows up in Indeed's assessments and catches candidates off-guard because the naive approach wastes a full tree traversal. You need to calculate the tilt at every node (absolute difference between left and right subtree sums) in a single pass. The trick is combining the sum calculation with tilt calculation during one DFS, not two separate traversals. It's the kind of problem where someone who hasn't seen it burns 10 minutes on an inefficient solution, while someone who has the pattern solves it in 90 seconds. If you blank on the optimization during your live assessment, StealthCoder surfaces a working solution invisibly so you stay ahead.
Companies that ask "Binary Tree Tilt"
Binary Tree Tilt is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe core pattern is a post-order DFS that returns the subtree sum while accumulating tilt at each node. The trap is computing tilts naively: calculate left sum, calculate right sum, compute tilt, then recurse. That's O(n^2) and slow. Instead, your recursive helper should return the sum of the current subtree while the parent scope tracks tilt. At each node, you have both sums available, so you compute tilt and add it to a counter in one step. The problem tests whether you can nest multiple computations into a single traversal. Most easy tree problems let you get away with messier code, but this one rewards clean recursion design. If you don't see the single-pass structure going in and you hit it on an assessment, StealthCoder handles the pattern instantly.
Pattern tags
You know the problem.
Make sure you actually pass it.
Binary Tree Tilt recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Binary Tree Tilt interview FAQ
Is Binary Tree Tilt actually easy or does it trick you?+
It's genuinely easy once you see the pattern, but the gotcha is solving it efficiently in one pass instead of two. The naive approach works but is slower. Acceptance rate is 64 percent, so most people solve it, but not always the optimal way. Tree traversal fundamentals matter here.
Is this still asked at companies like Indeed?+
Indeed has this in their question bank. It's not a trendy problem, but it stays because it's short enough for a timed assessment and tests whether you understand recursive tree patterns. It's more common at mid-size tech companies than unicorns.
What's the actual trick to Binary Tree Tilt?+
Combine sum and tilt calculation in the same DFS pass. Your recursive function returns the subtree sum to its parent, and you calculate and accumulate tilt at each node before returning. This avoids recalculating sums and keeps you at O(n) time and O(h) space for the call stack.
How does Binary Tree Tilt relate to other tree problems?+
It's a step up from basic traversal because it chains multiple outputs from one recursion. Similar patterns appear in Depth-First Search problems that compute path sums or validate trees. If you're comfortable with post-order traversal, tilt is the next logical difficulty.
Can I solve Binary Tree Tilt in an interview without seeing it before?+
Yes, but you need solid DFS instincts. If you understand how to write recursive helpers that return values up the tree, you can derive the pattern. The risk is spending 5 minutes on the wrong approach. Knowing the structure beforehand removes that risk.
Want the actual problem statement? View "Binary Tree Tilt" on LeetCode →