LeetCode 637. Average of Levels in Binary Tree

Problem Statement

// Definition for a binary tree node.
// #[derive(Debug, PartialEq, Eq)]
// pub struct TreeNode {
//   pub val: i32,
//   pub left: Option<Rc<RefCell<TreeNode>>>,
//   pub right: Option<Rc<RefCell<TreeNode>>>,
// }
// 
// impl TreeNode {
//   #[inline]
//   pub fn new(val: i32) -> Self {
//     TreeNode {
//       val,
//       left: None,
//       right: None
//     }
//   }
// }
use std::rc::Rc;
use std::cell::RefCell;

use std::collections::VecDeque;

impl Solution {
    pub fn average_of_levels(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<f64> {
        let mut ans = vec![];
        if root.is_none() {
            return ans;
        }

        let mut q = VecDeque::new();
        q.push_back(root.clone());
        while !q.is_empty() {
            let size = q.len();
            let mut sum : i64 = 0;
            let mut i = size;
            while i != 0 {
                if let Some(node) = q.pop_front() {
                    sum += node.clone().unwrap().borrow().val as i64;
                    let (left, right) = (
                        node.clone().unwrap().borrow().left.clone(),
                        node.clone().unwrap().borrow().right.clone()
                    );
                    if !left.is_none() {
                        q.push_back(left);
                    }
                    if !right.is_none() {
                        q.push_back(right);
                    }
                    i -= 1;
                }
            }
            ans.push(sum as f64 / size as f64);
        }
        return ans;
    }
}