maximum-depth-of-binary-tree-蒲公英云

maximum-depth-of-binary-tree

/**
* @author gentleKay
* 题目描述
* Given a binary tree, find its maximum depth.
* The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
* 给定二叉树，求其最大深度。
* 最大深度是从根节点到最远叶节点沿最长路径的节点数。
*/

/**
 * 
 * @author gentleKay
 * 题目描述
 * Given a binary tree, find its maximum depth.
 * The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
 * 给定二叉树，求其最大深度。
 * 最大深度是从根节点到最远叶节点沿最长路径的节点数。
 */
public class Main04 {
    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(Main04.maxDepth(root));
    }
    public static class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode(int x) { val = x; }
    }
    public static int maxDepth(TreeNode root) {
        if (root == null) {
            return 0;
        }
        if (root.left == null) {
            return maxDepth(root.right)+1;
        }
        if (root.right == null) {
            return maxDepth(root.left)+1;
        }
        return Math.max(maxDepth(root.right)+1, maxDepth(root.left)+1);
    }
}