Given a Binary Tree and a node x in it, find distance of the closest leaf to x in Binary Tree. If given node itself is a leaf, then distance is 0.
Input: Root of below tree And x = pointer to node 13 10 / \ 12 13 / 14 Output 1 Distance 1. Closest leaf is 14. Input: Root of below tree And x = pointer to node 13 10 / \ 12 13 / \ 14 15 / \ / \ 21 22 23 24 /\ /\ /\ /\ 1 2 3 4 5 6 7 8 Output 2 Closest leaf is 12 through 10.
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The idea is to first traverse the subtree rooted with give node and find the closest leaf in this subtree. Store this distance. Now traverse tree starting from root. If given node x is in left subtree of root, then find the closest leaf in right subtree, else find the closest left in left subtree. Below is the implementation of this idea.
The closest leaf to the node with value 13 is at a distance of 2
Time Complexity of this above solution is O(n) as it does at most two traversals of given Binary Tree.
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