use std::collections::HashMap;

fn main() {
    // (Key, value)
    let list = vec![(1, 2), (3, 4), (1, 1), (3, 6), (2, 8), (1, 3)];

    // Look for max value for each key in list
    let mut max = HashMap::new();

    for &(n, x) in &list {
        let mut cur_max = max.entry(n).or_insert(x);
        if x > *cur_max {
            *cur_max = x;
        }
    }

    println!("{:?}", max);
}