89 lines
2.4 KiB
Rust
89 lines
2.4 KiB
Rust
|
/**
|
||
|
|
* [139] Word Break
|
||
|
|
*/
|
||
|
|
pub struct Solution {}
|
||
|
|
|
||
|
|
|
||
|
|
// submission codes start here
|
||
|
|
use std::{rc::Rc, cell::RefCell, collections::HashMap};
|
||
|
|
|
||
|
|
struct Trie {
|
||
|
|
is_word: bool,
|
||
|
|
next: HashMap<char, Rc<RefCell<Trie>>>,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl Trie {
|
||
|
|
fn new(is_word: bool) -> Rc<RefCell<Self>> {
|
||
|
|
Rc::new(RefCell::new(Trie {
|
||
|
|
is_word,
|
||
|
|
next: HashMap::new(),
|
||
|
|
}))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
impl Solution {
|
||
|
|
pub fn word_break(s: String, word_dict: Vec<String>) -> bool {
|
||
|
|
let mut root = Trie::new(false);
|
||
|
|
|
||
|
|
// 建立字典树
|
||
|
|
for word in &word_dict {
|
||
|
|
let mut node = Rc::clone(&root);
|
||
|
|
|
||
|
|
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_word = true;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if i == word.len() - 1 {
|
||
|
|
node.borrow_mut().next.insert(c, Trie::new(true));
|
||
|
|
} else {
|
||
|
|
node.borrow_mut().next.insert(c, Trie::new(false));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
let tmp_node = Rc::clone(node.borrow().next.get(&c).unwrap());
|
||
|
|
node = tmp_node;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
let word: Vec<char> = s.chars().collect();
|
||
|
|
let n = s.len();
|
||
|
|
let mut dp = vec![false; n];
|
||
|
|
|
||
|
|
for i in 0..n {
|
||
|
|
if i > 0 && !dp[i - 1] {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
let mut node = Rc::clone(&root);
|
||
|
|
|
||
|
|
let mut pos = i;
|
||
|
|
while pos < n && node.borrow().next.contains_key(&word[pos]) {
|
||
|
|
let next_node = Rc::clone(node.borrow().next.get(&word[pos]).unwrap());
|
||
|
|
|
||
|
|
dp[pos] = next_node.borrow().is_word || dp[pos];
|
||
|
|
pos += 1;
|
||
|
|
node = next_node;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
dp[n - 1]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// submission codes end
|
||
|
|
|
||
|
|
#[cfg(test)]
|
||
|
|
mod tests {
|
||
|
|
use super::*;
|
||
|
|
|
||
|
|
#[test]
|
||
|
|
fn test_139() {
|
||
|
|
assert!(Solution::word_break("leetcode".to_owned(), vec_string!("leet", "code")));
|
||
|
|
assert!(Solution::word_break("applepenapple".to_owned(), vec_string!("apple", "pen")));
|
||
|
|
assert!(!Solution::word_break("catsandog".to_owned(), vec_string!("cats", "cat", "sand", "and", "cat")));
|
||
|
|
assert!(Solution::word_break("aaaaaaa".to_owned(), vec_string!("aaa", "aaaa")));
|
||
|
|
}
|
||
|
|
}
|