What is the time complexity of LeetCode 124 solution?

O(n)—visits each node once, constant work per node.

How does Binary Tree Maximum Path Sum handle all-negative trees?

Picks the largest (least negative) single node, since branches prune to 0.

Can I solve Binary Tree Maximum Path Sum without recursion?

Iterative stack possible, but uglier—recursion's clarity wins interviews.

LeetCode 124's Max Path Sum: Recursion's Sneaky Tree Conquest

LeetCode 124 has burned 62% of 2.3 million attempts. The fix? A recursion trick that ignores negatives and hunts peaks across branches.

theAIcatchup Apr 09, 2026 4 min read

Visual step-by-step trace of LeetCode 124 Binary Tree Maximum Path Sum recursion

⚡ Key Takeaways

Clamp subtree sums to 0 to dodge negatives—core to O(n) efficiency. 𝕏
Global max updated per-node with left+right+val; return only best branch. 𝕏
Mirrors Kadane's 1D max subarray, extended to trees—visualize with TraceLit. 𝕏

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#Binary Tree Maximum Path Sum #DFS #DFS recursion #Dynamic Programming #LeetCode 124 #Tree Algorithms #binary tree #maximum-path-sum #recursion #trace-lit

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Originally reported by dev.to

⚡ Key Takeaways

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