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==NULL)
return 0;
int l=minDepth(root->left);
int r=minDepth(root->right);
if(l==0&&r==0)
return 1;
if(l==0||r==0)
return l>r?l+1:r+1;
if(l!=0&&r!=0)
return l>r?r+1:l+1;
}
};