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Minimum Depth of a Binary Tree (easy)

Minimum Depth of a Binary Tree (easy)

Problem Statement

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

Example 1:

Example 2:

Try it yourself

Try solving this question here:

import java.util.*;
class TreeNode {
  int val;
  TreeNode left;
  TreeNode right;
  TreeNode(int x) {
    val = x;
  }
};
class MinimumBinaryTreeDepth {
  public static int findDepth(TreeNode root) {
    // TODO: Write your code here
    return -1;
  }
  public static void main(String[] args) {
    TreeNode root = new TreeNode(12);
    root.left = new TreeNode(7);
    root.right = new TreeNode(1);
    root.right.left = new TreeNode(10);
    root.right.right = new TreeNode(5);
    System.out.println("Tree Minimum Depth: " + MinimumBinaryTreeDepth.findDepth(root));
    root.left.left = new TreeNode(9);
    root.right.left.left = new TreeNode(11);
    System.out.println("Tree Minimum Depth: " + MinimumBinaryTreeDepth.findDepth(root));
  }
}

Solution

This problem follows the Binary Tree Level Order Traversal pattern. We can follow the same BFS approach. The only difference will be, instead of keeping track of all the nodes in a level, we will only track the depth of the tree. As soon as we find our first leaf node, that level will represent the minimum ...