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$ curl repovive.com/roadmaps/graph-theory/mixed-practice-tree-fundamentals/tree-diameter-implementation

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$ curl repovive.com/roadmaps/graph-theory/mixed-practice-tree-fundamentals/tree-diameter-implementation

Repovive

Tree Diameter - Implementation - Mixed Practice: Tree Fundamentals | Graph Theory | Repovive

Repovive.

Graph Theory37 sections · 1633 units81h total

Open in Course

Tree Diameter - Implementation

(DP approach)

I'll show the DP approach. For each node, track max depth and update global diameter:

ans = 0

function dfs(u, p):
    m1 = 0
    m2 = 0
    for v in adj[u]:
        if v == p:
            continue
        d = dfs(v, u)
        if d > m1:
            m2 = m1
            m1 = d
        else if d > m2:
            m2 = d
    ans = max(ans, m1 + m2)
    return m1 + 1

dfs(1, 0)
print ans

This runs in $O(n)$ time and uses $O(n)$ space.