Word break problem
Word break problem
You are encouraged to solve this task according to the task description, using any language you may know.
You are encouraged to solve this task according to the task description, using any language you may know.
Given an input string and a dictionary of words,
segment the input string into a space-separated sequence of dictionary words if possible.
Rust
Dynamic programming
<lang rust>use std::collections::HashSet; fn create_string(s: &str, v: Vec<Option<usize>>) -> String {
let mut idx = s.len(); let mut slice_vec = vec![]; while let Some(prev) = v[idx] { slice_vec.push(&s[prev..idx]); idx = prev; } slice_vec.reverse(); slice_vec.join(" ")
}
fn word_break(s: &str, dict: HashSet<&str>) -> Option<String> {
let size = s.len() + 1; let mut possible = vec![None; size];
let check_word = |i,j| dict.get(&s[i..j]).map(|_| i);
for i in 1..size { possible[i] = possible[i].or_else(|| check_word(0,i));
if possible[i].is_some() { for j in i+1..size { possible[j] = possible[j].or_else(|| check_word(i,j)); }
if possible[s.len()].is_some() { return Some(create_string(s, possible)); }
}; } None
}
fn main() {
let mut set = HashSet::new(); set.insert("a"); set.insert("bc"); set.insert("abc"); set.insert("cd"); set.insert("b"); println!("{:?}", word_break("abcd", set).unwrap());
}</lang>
- Output:
"a b cd"