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 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 == 0) return 0;   if (root->left == 0 && root->right == 0)   return 1;   else if (0 == root->left)   return 1 + minDepth(root->right);   else if (0 == root->right)   return 1 + minDepth(root->left);   else   {   int left = minDepth(root->left);   int right = minDepth(root->right);   return left <= right ? 1 + left : 1 + right;   }    }};