leetcode简单题19 N.100 相同的树 rust描述

// [1,2,3] [1,2,3] true
// [1,2] [1,null,2] false
// [1,2,1] [1,1,2] false
use std::rc::Rc;
use std::cell::RefCell;
#[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
    }
  }
}
// 递归解法
pub fn is_same_tree(p: Option<Rc<RefCell<TreeNode>>>, q: Option<Rc<RefCell<TreeNode>>>) -> bool {
    match (p, q) {
        (Some(p_node), Some(q_node)) => {
            let p_borrow = p_node.borrow();
            let q_borrow = q_node.borrow();
            p_borrow.val == q_borrow.val &&
                is_same_tree(p_borrow.left.clone(), q_borrow.left.clone()) &&
                is_same_tree(p_borrow.right.clone(), q_borrow.right.clone())
        }
        (None, None) => true,
        _ => false,
    }
}
// 迭代解法

pub fn is_same_tree2(p: Option<Rc<RefCell<TreeNode>>>, q: Option<Rc<RefCell<TreeNode>>>) -> bool {
    let mut stack = vec![(p, q)];

    while let Some((p, q)) = stack.pop() {
        match (p, q) {
            (Some(p_node), Some(q_node)) => {
                let p_borrow = p_node.borrow();
                let q_borrow = q_node.borrow();
                if p_borrow.val != q_borrow.val {
                    return false;
                }
                stack.push((p_borrow.left.clone(), q_borrow.left.clone()));
                stack.push((p_borrow.right.clone(), q_borrow.right.clone()));
            }
            (None, None) => continue,
            _ => return false,
        }
    }

        true
    }

fn main() {
    //根据[1,2,3] [1,2,3] true编写测试用例
    let tree1 = Some(Rc::new(RefCell::new(TreeNode {
        val:1,
        left:Some(Rc::new(RefCell::new(TreeNode {
            val:2,
            left:None,
            right:None,
        }))),
        right:Some(Rc::new(RefCell::new(TreeNode {
            val:3,
            left:None,
            right:None,
        }))),
    })));
    let tree2 = Some(Rc::new(RefCell::new(TreeNode {
        val:1,
        left:Some(Rc::new(RefCell::new(TreeNode {
            val:2,
            left:None,
            right:None,
        }))),
        right:Some(Rc::new(RefCell::new(TreeNode {
            val:3,
            left:None,
            right:None,
        }))),
    })));
    assert_eq!(is_same_tree(tree1.clone(), tree2.clone()), true);
    assert_eq!(is_same_tree2(tree1.clone(), tree2.clone()), true);
}