Leetcode Problem 1766. Tree of Coprimes

1766. Tree of Coprimes

Leetcode Solutions

DFS with Ancestor Tracking and Co-prime Caching

  1. Precompute a list of co-prime numbers for each number from 1 to 50.
  2. Initialize a map to keep track of the latest ancestors for each unique value encountered during DFS, along with their depths.
  3. Perform a DFS starting from the root node.
  4. For the current node, iterate over its value's co-prime list and check against the ancestor map to find the closest ancestor with a co-prime value.
  5. Update the result for the current node with the closest ancestor's index.
  6. Before traversing child nodes, update the ancestor map with the current node's value and depth.
  7. After traversing child nodes, remove the current node from the ancestor map to prevent it from being considered as an ancestor for its siblings or cousin nodes.
  8. Continue the DFS until all nodes have been visited.
  9. Return the result array containing the closest co-prime ancestors for each node.
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Brute Force with GCD Computation

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