hello-algo/codes/rust/chapter_backtracking/preorder_traversal_iii_compact.rs

56 lines
1.5 KiB
Rust
Raw Normal View History

/*
* File: preorder_traversal_iii_compact.rs
* Created Time: 2023-07-15
* Author: codingonion (coderonion@gmail.com)
*/
include!("../include/include.rs");
use std::{cell::RefCell, rc::Rc};
use tree_node::{vec_to_tree, TreeNode};
/* 前序遍历:例题三 */
fn pre_order(
res: &mut Vec<Vec<Rc<RefCell<TreeNode>>>>,
path: &mut Vec<Rc<RefCell<TreeNode>>>,
root: Option<&Rc<RefCell<TreeNode>>>,
) {
// 剪枝
if root.is_none() || root.as_ref().unwrap().borrow().val == 3 {
return;
}
if let Some(node) = root {
// 尝试
path.push(node.clone());
if node.borrow().val == 7 {
// 记录解
res.push(path.clone());
}
pre_order(res, path, node.borrow().left.as_ref());
pre_order(res, path, node.borrow().right.as_ref());
// 回退
path.pop();
}
}
/* Driver Code */
pub fn main() {
let root = vec_to_tree([1, 7, 3, 4, 5, 6, 7].map(|x| Some(x)).to_vec());
println!("初始化二叉树");
print_util::print_tree(root.as_ref().unwrap());
// 前序遍历
let mut path = Vec::new();
let mut res = Vec::new();
pre_order(&mut res, &mut path, root.as_ref());
println!("\n输出所有根节点到节点 7 的路径,路径中不包含值为 3 的节点");
for path in res {
let mut vals = Vec::new();
for node in path {
vals.push(node.borrow().val)
}
println!("{:?}", vals);
}
}