Add to List 111. Minimum Depth of Binary Tree（LeetCode）

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;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int minDepth(TreeNode* root) {
          int left = 0;
        int right = 0;
        if (root == NULL)
            return 0;
        if (root->left != NULL)
            left = minDepth(root->left);
        if (root->right != NULL)
            right = minDepth(root->right);
        return 1 + (min(left, right) ? min(left, right) : max(left, right));
    }
};