Reroot DP Max Distance

Problem

Compute the eccentricity of every node of a tree with the rerooting technique.

First compute downward heights with a post-order pass, then propagate best distances from the parent side using the two largest child heights. Return the maximum distance from each node. edges is a list of [u, v] pairs; the tree is rooted at 0 internally.

Hint

Each node uses the best child path plus the best path through its parent.

Test cases

case 1

in: [4,[[0,1],[1,2],[2,3]]]

expected: [3,2,2,3]

case 2

in: [4,[[0,1],[0,2],[0,3]]]

expected: [1,2,2,2]

case 3

in: [1,[]]

expected: [0]

case 4

in: [2,[[0,1]]]

expected: [1,1]

Starter codePython

def reroot_max_distance(n, edges):
    # Your code here
    pass

4 test cases · run your code against them in the editor