Cinte's Leetcode Record
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104. Maximum Depth of Binary Tree

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104. Maximum Depth of Binary Tree

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        int depth{ 0 };
        int tmp{ 0 };
        backTrack(root, depth, tmp);
        return depth;
    }
private:
    void backTrack(TreeNode* root, int& depth, int& tmp)
    {
        if(!root) return;
        ++tmp;
        depth = max(depth, tmp);
        backTrack(root->left, depth, tmp);
        backTrack(root->right, depth, tmp);
        --tmp;
    }
};
review
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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int maxDepth(TreeNode* root) {
        if(!root)
            return 0;
        return max(maxDepth(root->left) + 1, maxDepth(root->right) + 1);
    }
};

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