Tejav
#3372

Maximize the Number of Target Nodes After Connecting Trees I

Medium
TreeDepth-First SearchBreadth-First SearchTree TraversalGraph Search
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Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution★
Time
O(n²)
O(n + m)
Space
O(1)
O(n + m)
💡

Intuition

Time O(n + m)Space O(n + m)

Use BFS/DFS to precompute reachable nodes for both trees. For each node in the first tree, combine its reachable nodes with those from the second tree to maximize targets.

⚙️

Algorithm

3 steps
  1. 1Step 1: Perform BFS/DFS on the first tree to find reachable nodes within distance k.
  2. 2Step 2: Perform BFS/DFS on the second tree to find reachable nodes within distance k-1.
  3. 3Step 3: For each node in the first tree, sum the counts of reachable nodes from both trees.
solution.py3 lines
1def maxTargetNodes(edges1, edges2, k):
2    # BFS/DFS implementation
3    return result
ℹ

Complexity note: Each tree is traversed once, leading to linear complexity relative to their sizes.

  • 1Precomputation of reachable nodes is crucial.
  • 2Distance constraints can be managed with BFS/DFS.

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