二叉树最小深度

Question:

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) {}
 * };
 */
#define INF_MAX 10000000000;
class Solution {
public:
    int minDepth(TreeNode* root) {
        if(root == 0) return 0;
        if(!root -> left) return minDepth(root -> right) + 1;
        if(!root -> right) return minDepth(root -> left) + 1;
        return min(minDepth(root -> left) + 1 , minDepth(root -> right) + 1);
    }
};