Easy

Quiz

#111 Minimum Depth of Binary Tree

APPROACH

Find the minimum depth of a binary tree.

The minimum depth is the number of nodes along the shortest path from the root to the nearest leaf node.

Note: A leaf is a node with no children.

Example 1:

Input: root = [3,9,20,null,null,15,7]

Output: 2

Example 2:

Input: root = [2,null,3,null,4,null,5,null,6]

Output: 5

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What is the optimal approach for this problem?