📄️ Pattern 6: DP on Trees Problems
The Hierarchical Pattern: State is dpnode] or dp[node = answer for subtree rooted at node. DFS/post-order traversal to combine children's solutions.
Pattern 9: DP on Trees Problems
The Hierarchical Pattern: State is dp[node] = answer for subtree rooted at node. DFS/post-order traversal to combine children's solutions. ~3% of interview problems.