Longest prefix in a list of strings

main.rs

use std::collections::HashMap;

#[derive(Clone)]
pub struct Node {
    end: bool,
    next: HashMap<char, Node>,
}

pub struct Trie {
    root: Node,
}

impl Trie {
    pub fn new() -> Self {
        Self {
            root: Node {
                end: false,
                next: HashMap::new(),
            },
        }
    }

    pub fn insert(&mut self, s: String) {
        let mut node = &mut self.root;

        for c in s.chars() {
            if !node.next.contains_key(&c) {
                node.next.insert(
                    c,
                    Node {
                        end: false,
                        next: HashMap::new(),
                    },
                );
            }
            node = node.next.get_mut(&c).unwrap();
        }
        node.end = true;
    }

    pub fn longest_prefix(strs: Vec<String>) -> String {
        if strs.len() == 0 {
            return String::from("");
        }

        if strs.len() == 1 {
            return strs[0].clone();
        }

        let mut t = Self::new();
        for s in &strs {
            if s.len() == 0 {
                return String::from("");
            }
            t.insert(s.to_string());
        }

        let mut max = 0;
        let mut node = &t.root;
        while node.next.len() == 1 && !node.end {
            node = node.next.get(&strs[0].chars().nth(max).unwrap()).unwrap();
            max += 1;
        }

        String::from(&strs[0][0..max])
    }
}

fn main() {
    let inputs: Vec<String> = vec![
        "cranberry".to_string(),
        "crawfish".to_string(),
        "crap".to_string(),
    ];

    println!("longest prefix: {}", Trie::longest_prefix(inputs));
}