minimum_depth_of_binary_tree.rs

impl Solution {
    pub fn min_depth(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {
        match root {
            Some(node) => {
                let left = Self::min_depth(node.borrow().left.clone());
                let right = Self::min_depth(node.borrow().right.clone());

                if left == 0 || right == 0 {
                    left.max(right) + 1
                } else {
                    left.min(right) + 1
                }
            }

            None => 0,
        }
    }
}