面试题55-题目一：二叉树的深度

/*

 * 面试题55-题目一：二叉树的深度

 * 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。

 * 思路：树的深度就是：左右子树的较大值加1.

 */

class TreeNode6 {

    int val = 0;

    TreeNode6 left = null;

    TreeNode6 right = null;

 

    public TreeNode6(int val) {

        this.val = val;

 

    }

}

 

public class No55TreeDepth {

 

    public static void main(String[] args) {

       No55TreeDepth n = new No55TreeDepth();

       TreeNode6 root = new TreeNode6(1);

       TreeNode6 p2 = new TreeNode6(2);

       TreeNode6 p3 = new TreeNode6(3);

       TreeNode6 p4 = new TreeNode6(4);

       TreeNode6 p5 = new TreeNode6(5);

       TreeNode6 p6 = new TreeNode6(6);

       TreeNode6 p7 = new TreeNode6(7);

       root.left = p2;

       root.right = p3;

       p2.left = p4;

       p2.right = p5;

       p5.left = p7;

       p3.right = p6;

      

       System.out.println(n.TreeDepth(root));

 

    }

 

    public int TreeDepth(TreeNode6 root) {

       if (root == null) {

           return 0;

       }

       //求左右子树的深度

       int nLeft = TreeDepth(root.left);

       int nRight = TreeDepth(root.right);

       //返回大值加1即为树的深度

       return (nLeft > nRight) ? (nLeft + 1) : (nRight + 1);

    }

 

}