minimum-depth-of-binary-tree

Posted 2022-05-03 strive-19970713

题目描述

Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

/**
 * @author gentleKay
 * Given a binary tree, find its minimum depth.   给定二叉树，求其最小深度。
 * The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.
 * 最小深度是从根节点到最近的叶节点沿最短路径的节点数。
 */

public class Main01 

	public static void main(String[] args) 
		// TODO Auto-generated method stub
		TreeNode root = new TreeNode(4);
		root.left = new TreeNode(2);
		root.left.left = new TreeNode(1);
		root.left.right  = new TreeNode(3);
		
		root.right = new TreeNode(6);
		root.right.left = new TreeNode(5);
		root.right.right = new TreeNode(7);
		root.right.right.right = new TreeNode(8);
		System.out.println(Main01.run(root));
	
	
	public static class TreeNode 
		int val;
		TreeNode left;
		TreeNode right;
		TreeNode(int x)  val = x; 
	
	
	public static int run(TreeNode root) 
		
		if (root == null) 
			return 0;
		
		if (root.left == null) 
			return run(root.right) + 1;
		
		
		if (root.right == null) 
			return run(root.left) + 1;
		
		return Math.min(run(root.left)+1, run(root.right)+1);