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.

思路:求二叉树最小深度，典型的递归。直接上代码吧，都看得明白。

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int depth(TreeNode *root)
    {
        if(root==NULL)
            return 0;
        else if(root->left==NULL && root->right==NULL)
            return 1;
        else
        {
            if(root->left==NULL)
                return depth(root->right)+1;
            else if(root->right==NULL)
                return depth(root->left)+1;
            else
            {
                int leftMin=depth(root->left);
                int rightMin=depth(root->right);
                return (leftMin>rightMin?rightMin:leftMin)+1;
            }
        }
    }
    int minDepth(TreeNode *root) {
        depth(root);
    }
};