use std::collections::HashMap;

fn tokenize(s: &str) -> Vec<String> {
    let mut tokens = Vec::new();
    let mut current = String::new();
    for c in s.chars() {
        if c.is_alphanumeric() || c == '_' {
            current.push(c);
        } else if !current.is_empty() {
            tokens.push(std::mem::take(&mut current));
        }
    }
    if !current.is_empty() {
        tokens.push(current);
    }

    tokens
}

fn is_numeric_token(s: &str) -> bool {
    s.parse::<f64>().is_ok()
}

fn plagiarism_check(code1: &[String], code2: &[String]) -> bool {
    let c1 = code1.join(" ");
    let c2 = code2.join(" ");
    if c1 == c2 {
        return false;
    }

    let d1 = tokenize(&c1);
    let d2 = tokenize(&c2);

    let mut r_cand: HashMap<String, String> = HashMap::new();
    for (v, w) in d1.iter().zip(d2.iter()) {
        if v != w && !is_numeric_token(v) {
            r_cand.insert(v.clone(), w.clone());
        }
    }

    let renamed: Vec<String> = d1
        .iter()
        .map(|t| r_cand.get(t).cloned().unwrap_or_else(|| t.clone()))
        .collect();

    renamed == d2
}