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.

/**
* 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) {
if(!root){
return 0;
}
if(!root->left && !root->right){
return 1;
}
if(!root->left){
return minDepth(root->right)+1;
}
if(!root->right){
return minDepth(root->left)+1;
}
int leftDepth = minDepth(root->left);
int rightDepth = minDepth(root->right);
return (leftDepth < rightDepth)?(leftDepth+1):(rightDepth+1);
}
};