LeetCode Q104: Maximum Depth of Binary Tree

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.

	/**
	* Definition for a binary tree node.
	* struct TreeNode {
	* int val;
	* TreeNode *left;
	* TreeNode *right;
	* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
	* };
	*/
	class Solution {
	public:
	int helper(TreeNode* node, int depth){
	if(node==NULL)
	return depth;
	int d0=depth;
	int d1=depth;
	if(node->left!=NULL)
	d0=helper(node->left, depth+1);
	if(node->right!=NULL)
	d1=helper(node->right, depth+1);
	return max(d0, d1);
	}
	int maxDepth(TreeNode* root) {
	if(root==NULL)
	return 0;
	return helper(root, 1);
	}
	};

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Round2 solution:

	class Solution {
	public:
	void DFS(TreeNode* root, int& maxDepth, int curDepth){
	if(root==NULL)
	return;
	maxDepth=max(maxDepth, curDepth);
	DFS(root->left, maxDepth, curDepth+1);
	DFS(root->right, maxDepth, curDepth+1);
	}
	int maxDepth(TreeNode* root) {
	int depth=0;
	if(root==NULL)
	return depth;
	DFS(root, depth, 1);
	return depth;
	}
	};

view raw Q104.cpp hosted with ❤ by GitHub