Leetcode 111 Solution

This article provides solution to leetcode question 111 (minimum-depth-of-binary-tree)

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

Solution

/**
 * 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 minDepth(TreeNode* root) {
        if (root == NULL)
            return 0;

        int left_depth = minDepth(root->left);
        int right_depth = minDepth(root->right);

        if (left_depth == 0 && right_depth == 0)
            return 1;
        else if (left_depth == 0)
            return right_depth + 1;
        else if (right_depth == 0)
            return left_depth + 1;
        else
            return min(left_depth, right_depth) + 1;
    }
};