##Description 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. ##Solution
/**
* 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 minDepth(TreeNode *root) {
if(!root) return 0;
if(!root->left && !root->right) return 1;
if(!root->left) return 1 + minDepth(root->right);
if(!root->right) return 1 + minDepth(root->left);
return 1 + min(minDepth(root->left), minDepth(root->right));
}
};