Maximum Depth of Binary Tree

题目：

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.

 

 

题解：

与minimum代码几乎完全一样，只需要修改math.min为math.max

public class Solution {
    public int maxDepth(TreeNode root) {
        if (root == null) {
            return 0;
        }
        return getMin(root);
    }

    public int getMin(TreeNode root){
        if (root == null) {
            return Integer.MIN_VALUE;
        }

        if (root.left == null && root.right == null) {
            return 1;
        }

        return Math.max(getMin(root.left), getMin(root.right)) + 1;
    }
}

 

 用divide and conquer

public class Solution {
    public int maxDepth(TreeNode root) 
    {
        if (root==null) return 0;
        int left=maxDepth(root.left);
        int right=maxDepth(root.right);
        return Math.max(left,right)+1;
        
    }
}