Binary Tree part 2

104. Maximum Depth of Binary Tree

https://leetcode.com/problems/maximum-depth-of-binary-tree/

/**
 * 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){
        int left = node->left?helper(node->left, depth+1):depth;
        int right = node->right?helper(node->right, depth+1):depth;
        return max(left, right);
        
    }
    int maxDepth(TreeNode* root) {
        if(!root)return 0;
        return helper(root, 1);    
    }
};

We can make it concisely in one line.

/**
 * 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 maxDepth(TreeNode* root) {
       return root?1+max(maxDepth(root->left), maxDepth(root->right)):0;   
    }
}

543. Diameter of Binary Tree

Diameter of Binary Tree - LeetCode

/**
 * 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 length = 0;
    int depth(TreeNode* root) {
        if (!root)return 0;
        int left = depth(root->left), right = depth(root->right);
        length = max(length, left+right);
        return max(left,right)+1;
        
    }
    int diameterOfBinaryTree(TreeNode* root) {
        depth(root);
        return length;   
    }
};