104. Maximum Depth of Binary Tree

求一棵二叉树的最大深度

思路：递归

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class Solution:
    def maxDepth(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        # 5 star
        if not root:
            return 0
        return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1

Go:

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func maxDepth(root *TreeNode) int {
	if root == nil {return 0}
	return max(maxDepth(root.Left), maxDepth(root.Right)) + 1

}

func max(a, b int) int {
	if a > b {return a}
	return b
}