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Find a root node in a directed tree that minimizes the number of edge reversals required to make all edges point away from it.
The input guarantees a tree structure with exactly n-1 directed edges connecting n nodes.
Evaluate every possible root choice and return the smallest reversal count.
What This Tests
Tree and graph traversal techniques
Rerooting dynamic programming concept
State propagation and incremental cost updates
Transforming directed graphs into weighted structures
Common Patterns
Graph Traversal
DFS/BFS
Dynamic Programming
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