balanced_binary_tree.rs

use std::rc::Rc;
use std::cell::RefCell;
impl Solution {
    pub fn is_balanced(root: Option<Rc<RefCell<TreeNode>>>) -> bool {
        match root {
            None => true,
            Some(curr_node) =>{
                let curr_node = curr_node.borrow();
                
                let left  = Self::height(curr_node.left.clone());
                let right = Self::height(curr_node.right.clone());
                let diff  = i32::abs(left-right);
                
                if(diff <= 1){
                    return Self::is_balanced(curr_node.left.clone()) && Self::is_balanced(curr_node.right.clone());
                }
                
                return false;
            }
        }
    }
    
    pub fn height(root: Option<Rc<RefCell<TreeNode>>>) -> i32{
        match root {
            None => 0,
            Some(curr_node) => {
                let curr_node = curr_node.borrow();
                1 + std::cmp::max( Self::height(curr_node.left.clone()), Self::height(curr_node.right.clone()) )
            }
        }
   }
}