Maximum Depth of Binary Tree

问题：二叉树的最深深度

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class Solution { public:     void dfs(TreeNode *root,int step,int &MAX)     {         if(root==NULL)         {             if(MAX<step) MAX=step;             return ;         }         dfs(root->left,step+1);         dfs(root->right,step+1);     }     int maxDepth(TreeNode *root)     {         int MAX=0;         dfs(root,step,MAX);         return MAX;     } };

 

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class Solution { public:     int maxDepth(TreeNode *root) {         if(root==NULL) return 0;         int leftDepth=maxDepth(root->left);         int rightDepth=maxDepth(root->right);         return max(leftDepth,rightDepth)+1;     } };