LeetCode 111. Minimum Depth of Binary Tree

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.

解法：利用递归

/**

 * 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 Mymin(int a , int b) {
    if (a > b) return b;
        return a;
    }
    int minDepth(TreeNode* root) {
        if (root == NULL) return 0;
        int left = minDepth(root->left);
        int right = minDepth(root->right);
        return (root->left == NULL || root->right == NULL) ? left + right + 1 : Mymin(left , right) + 1;
    }
};