20240630 Finished

This commit is contained in:
jackfiled 2024-06-30 13:09:37 +08:00
parent e760e2168a
commit d57286d7c8
2 changed files with 128 additions and 1 deletions

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@ -162,3 +162,4 @@ mod p210_course_schedule_ii;
mod p909_snakes_and_ladders; mod p909_snakes_and_ladders;
mod p433_minimum_genetic_mutation; mod p433_minimum_genetic_mutation;
mod p127_word_ladder; mod p127_word_ladder;
mod p208_implement_trie_prefix_tree;

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@ -0,0 +1,126 @@
/**
* [208] Implement Trie (Prefix Tree)
*/
pub struct Solution {}
// submission codes start here
use std::{cell::RefCell, collections::HashMap, rc::Rc};
#[derive(Debug)]
struct TrieNode {
is_ended: bool,
next: HashMap<char, Rc<RefCell<TrieNode>>>,
}
impl TrieNode {
fn new(is_ended: bool) -> Self {
TrieNode {
is_ended,
next: HashMap::new(),
}
}
}
struct Trie {
head: Rc<RefCell<TrieNode>>,
}
/**
* `&self` means the method takes an immutable reference.
* If you need a mutable reference, change it to `&mut self` instead.
*/
impl Trie {
fn new() -> Self {
Trie {
head: Rc::new(RefCell::new(TrieNode::new(false))),
}
}
fn insert(&mut self, word: String) {
let mut node = Rc::clone(&self.head);
for (i, c) in word.chars().enumerate() {
if node.borrow().next.contains_key(&c) {
if i == word.len() - 1 {
node.borrow().next.get(&c).unwrap().borrow_mut().is_ended = true;
}
} else {
if i == word.len() - 1 {
node.borrow_mut()
.next
.insert(c, Rc::new(RefCell::new(TrieNode::new(true))));
} else {
node.borrow_mut()
.next
.insert(c, Rc::new(RefCell::new(TrieNode::new(false))));
}
}
let tmp_node = Rc::clone(node.borrow().next.get(&c).unwrap());
node = tmp_node;
}
}
fn search(&self, word: String) -> bool {
let mut node = Rc::clone(&self.head);
for (i, c) in word.chars().enumerate() {
if !node.borrow().next.contains_key(&c) {
return false;
}
if i == word.len() - 1 {
if !node.borrow().next.get(&c).unwrap().borrow().is_ended {
return false;
}
}
let tmp_node = Rc::clone(node.borrow().next.get(&c).unwrap());
node = tmp_node;
}
true
}
fn starts_with(&self, prefix: String) -> bool {
let mut node = Rc::clone(&self.head);
for c in prefix.chars() {
if !node.borrow().next.contains_key(&c) {
return false;
}
let tmp_node = Rc::clone(node.borrow().next.get(&c).unwrap());
node = tmp_node;
}
true
}
}
/**
* Your Trie object will be instantiated and called as such:
* let obj = Trie::new();
* obj.insert(word);
* let ret_2: bool = obj.search(word);
* let ret_3: bool = obj.starts_with(prefix);
*/
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_208() {
let mut trie = Trie::new();
trie.insert("app".to_owned());
assert!(!trie.search("ap".to_owned()));
trie.insert("ap".to_owned());
assert!(trie.search("ap".to_owned()));
}
}