[leetcode-111-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.*/
    int minDepth(TreeNode *root)
    {
        if(root == NULL) return 0;        
        if (root->left==NULL) return 1 + minDepth(root->right);
        if (root->right == NULL) return 1 + minDepth(root->left);
        return 1 + min(minDepth(root->left), minDepth(root->right));        
    }