rustlings/solutions/11_hashmaps/hashmaps3.rs
2024-07-04 13:38:35 +02:00

83 lines
2.6 KiB
Rust

// A list of scores (one per line) of a soccer match is given. Each line is of
// the form "<team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>"
// Example: "England,France,4,2" (England scored 4 goals, France 2).
//
// You have to build a scores table containing the name of the team, the total
// number of goals the team scored, and the total number of goals the team
// conceded.
use std::collections::HashMap;
// A structure to store the goal details of a team.
#[derive(Default)]
struct Team {
goals_scored: u8,
goals_conceded: u8,
}
fn build_scores_table(results: &str) -> HashMap<&str, Team> {
// The name of the team is the key and its associated struct is the value.
let mut scores = HashMap::new();
for line in results.lines() {
let mut split_iterator = line.split(',');
// NOTE: We use `unwrap` because we didn't deal with error handling yet.
let team_1_name = split_iterator.next().unwrap();
let team_2_name = split_iterator.next().unwrap();
let team_1_score: u8 = split_iterator.next().unwrap().parse().unwrap();
let team_2_score: u8 = split_iterator.next().unwrap().parse().unwrap();
// Insert the default with zeros if a team doesn't exist yet.
let team_1 = scores.entry(team_1_name).or_insert_with(Team::default);
// Update the values.
team_1.goals_scored += team_1_score;
team_1.goals_conceded += team_2_score;
// Similarely for the second team.
let team_2 = scores.entry(team_2_name).or_insert_with(Team::default);
team_2.goals_scored += team_2_score;
team_2.goals_conceded += team_1_score;
}
scores
}
fn main() {
// You can optionally experiment here.
}
#[cfg(test)]
mod tests {
use super::*;
const RESULTS: &str = "England,France,4,2
France,Italy,3,1
Poland,Spain,2,0
Germany,England,2,1
England,Spain,1,0";
#[test]
fn build_scores() {
let scores = build_scores_table(RESULTS);
assert!(["England", "France", "Germany", "Italy", "Poland", "Spain"]
.into_iter()
.all(|team_name| scores.contains_key(team_name)));
}
#[test]
fn validate_team_score_1() {
let scores = build_scores_table(RESULTS);
let team = scores.get("England").unwrap();
assert_eq!(team.goals_scored, 6);
assert_eq!(team.goals_conceded, 4);
}
#[test]
fn validate_team_score_2() {
let scores = build_scores_table(RESULTS);
let team = scores.get("Spain").unwrap();
assert_eq!(team.goals_scored, 0);
assert_eq!(team.goals_conceded, 3);
}
}