leetcode/tree/easy/is_subtree/src/lib.rs at master · zhangyuang/leetcode · GitHub

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/*
 * @lc app=leetcode.cn id=572 lang=rust
 *
 * [572] 另一个树的子树
 */

// #[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,
        }
    }
}
struct Solution {}
// @lc code=start
// 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::cell::RefCell;
use std::rc::Rc;
impl Solution {
    pub fn is_subtree(s: Option<Rc<RefCell<TreeNode>>>, t: Option<Rc<RefCell<TreeNode>>>) -> bool {
        if t.is_none() {
            return true;
        }
        if s.is_none() {
            return false;
        }
        let s_borrow = s.as_ref().unwrap().borrow();
        let s_left = if s_borrow.left.is_some() {
            Some(Rc::clone(s_borrow.left.as_ref().unwrap()))
        } else {
            None
        };
        let s_right = if s_borrow.right.is_some() {
            Some(Rc::clone(s_borrow.right.as_ref().unwrap()))
        } else {
            None
        };
        return Self::is_subtree(s_left, Some(Rc::clone(t.as_ref().unwrap())))
            || Self::is_subtree(s_right.clone(), Some(Rc::clone(t.as_ref().unwrap())))
            || Self::dfs(&s, &t);
    }
    fn dfs(s: &Option<Rc<RefCell<TreeNode>>>, t: &Option<Rc<RefCell<TreeNode>>>) -> bool {
        if s.is_none() && t.is_none() {
            return true;
        }
        if s.is_none() || t.is_none() {
            return false;
        }
        let s_borrow = s.as_ref().unwrap().borrow();
        let s_val = s_borrow.val;
        let s_left = &s_borrow.left;
        let s_right = &s_borrow.right;
        let t_borrow = t.as_ref().unwrap().borrow();
        let t_val = t_borrow.val;
        let t_left = &t_borrow.left;
        let t_right = &t_borrow.right;
        if s_val != t_val {
            return false;
        }
        return Self::dfs(s_left, t_left) && Self::dfs(s_right, t_right);
    }
}
// @lc code=end