题目

输入一棵二叉树，求该树的深度。从根结点到叶结点依次经过的结点（含根、叶结点）形成树的一条路径，最长路径的长度为树的深度。

解题

package demo18;class TreeNode {    int val = 0;    TreeNode left = null;    TreeNode right = null;    public TreeNode(int val) {        this.val = val;    }}/** * 获取二叉树深度 * @author mengfeiyang * */public class Solution2 {    public int TreeDepth(TreeNode pRoot){        if(pRoot ==null)            return 0;        int nLeft=TreeDepth(pRoot.left);        int nRight=TreeDepth(pRoot.right);        return nLeft>nRight?(nLeft+1):(nRight+1);    }        /**     * 测试     * @param args     */    public static void main(String[] args) {    	Solution2 s2 = new Solution2();    	/**    	 * 构造二叉树         	 *       1    	 *      / \    	 *     2   3    	 *    / \ / \    	 *   4  5 6  7    	 */		TreeNode root = new TreeNode(1);		TreeNode left = new TreeNode(2);		TreeNode right = new TreeNode(3);				TreeNode left_1 = new TreeNode(4);		TreeNode right_1 = new TreeNode(5);		TreeNode right_2 = new TreeNode(6);		TreeNode left_2 = new TreeNode(7);				left.left = left_1;		left.right = right_1;		right.left = left_2;		right.right = right_2;				root.left = left;		root.right = right;				System.out.println(s2.TreeDepth(root));// 输出结果为：3	}}