Maximum & Minimum 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;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int maxDepth(struct TreeNode* root) {
    int left, right;
    if(root == NULL)
        return 0;
    else
    {
        left = maxDepth(root->left) + 1;
        right = maxDepth(root->right) + 1;
        return (((left - right) > 0) ? left : right);
    }
}

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int minDepth(struct TreeNode* root) {
    int left, right;
    if(root == NULL)
        return 0;
    else if(root->left == NULL && root->right == NULL)
        return 1;
    else if(root->left == NULL && root->right != NULL)
        return minDepth(root->right) + 1;
    else if(root->right == NULL && root->left != NULL)
        return minDepth(root->left) + 1;
    else
    {
        left = minDepth(root->left) + 1;
        right = minDepth(root->right) + 1;
        return ((left > right) ? right : left);
    }
}