frog_river_one.rs

use std::collections::HashMap;

pub fn solution(x: i32, a: &Vec<i32>) -> i32 {
    let mut step = HashMap::new();

    for (i, s) in a.iter().enumerate() {
        step.entry(*s).or_insert(true);

        if step.len() == x as usize {
            return i as i32;
        }
    }

    -1
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_frog_river_one() {
        assert_eq!(solution(5, vec![1, 3, 1, 4, 2, 3, 5, 4].as_ref()), 6);
    }
}