LeetCode: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.

 1 class Solution{
 2 public:
 3     int minDepth(TreeNode *root){
 4         if(root==NULL)
 5         {
 6             return 0;
 7         }
 8         if(root->left==NULL&&root->right==NULL)
 9         {
10             return 1;
11         }
12         else
13         {
14             int a=minDepth(root->left);
15             int b=minDepth(root->right);
16             if(a==0||b==0)
17             {
18                 return (a>b?a:b)+1;
19             }
20             else
21             {
22                 return (a<b?a:b)+1;
23             }
24         }
25     }
26 };