diff options
| -rw-r--r-- | exercises/11_hashmaps/hashmaps3.rs | 71 | ||||
| -rw-r--r-- | rustlings-macros/info.toml | 12 | ||||
| -rw-r--r-- | solutions/11_hashmaps/hashmaps3.rs | 84 |
3 files changed, 122 insertions, 45 deletions
diff --git a/exercises/11_hashmaps/hashmaps3.rs b/exercises/11_hashmaps/hashmaps3.rs index 070c370..9f8fdd7 100644 --- a/exercises/11_hashmaps/hashmaps3.rs +++ b/exercises/11_hashmaps/hashmaps3.rs @@ -1,39 +1,38 @@ // 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). +// 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. One approach to build the scores table is to use a Hashmap. -// The solution is partially written to use a Hashmap, -// complete it to pass the test. -// -// Make me pass the tests! +// 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: String) -> HashMap<String, Team> { +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<String, Team> = HashMap::new(); + 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(); - for r in results.lines() { - let v: Vec<&str> = r.split(',').collect(); - let team_1_name = v[0].to_string(); - let team_1_score: u8 = v[2].parse().unwrap(); - let team_2_name = v[1].to_string(); - let team_2_score: u8 = v[3].parse().unwrap(); - // TODO: Populate the scores table with details extracted from the - // current line. Keep in mind that goals scored by team_1 - // will be the number of goals conceded by team_2, and similarly - // goals scored by team_2 will be the number of goals conceded by - // team_1. + // TODO: Populate the scores table with the extracted details. + // Keep in mind that goals scored by team 1 will be the number of goals + // conceded by team 2. Similarly, goals scored by team 2 will be the + // number of goals conceded by team 1. } + scores } @@ -45,40 +44,34 @@ fn main() { mod tests { use super::*; - fn get_results() -> String { - let results = "".to_string() - + "England,France,4,2\n" - + "France,Italy,3,1\n" - + "Poland,Spain,2,0\n" - + "Germany,England,2,1\n"; - results - } + 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(get_results()); + let scores = build_scores_table(RESULTS); - let mut keys: Vec<&String> = scores.keys().collect(); - keys.sort(); - assert_eq!( - keys, - vec!["England", "France", "Germany", "Italy", "Poland", "Spain"] - ); + 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(get_results()); + let scores = build_scores_table(RESULTS); let team = scores.get("England").unwrap(); - assert_eq!(team.goals_scored, 5); + assert_eq!(team.goals_scored, 6); assert_eq!(team.goals_conceded, 4); } #[test] fn validate_team_score_2() { - let scores = build_scores_table(get_results()); + let scores = build_scores_table(RESULTS); let team = scores.get("Spain").unwrap(); assert_eq!(team.goals_scored, 0); - assert_eq!(team.goals_conceded, 2); + assert_eq!(team.goals_conceded, 3); } } diff --git a/rustlings-macros/info.toml b/rustlings-macros/info.toml index 0da573b..c5ce847 100644 --- a/rustlings-macros/info.toml +++ b/rustlings-macros/info.toml @@ -574,16 +574,18 @@ https://doc.rust-lang.org/stable/book/ch08-03-hash-maps.html#only-inserting-a-va name = "hashmaps3" dir = "11_hashmaps" hint = """ -Hint 1: Use the `entry()` and `or_insert()` methods of `HashMap` to insert - entries corresponding to each team in the scores table. +Hint 1: Use the `entry()` and `or_insert()` (or `or_insert_with()`) methods of + `HashMap` to insert the default value of `Team` if a team doesn't + exist in the table yet. -Learn more at https://doc.rust-lang.org/stable/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value +Learn more in The Book: +https://doc.rust-lang.org/stable/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value Hint 2: If there is already an entry for a given key, the value returned by `entry()` can be updated based on the existing value. -Learn more at https://doc.rust-lang.org/book/ch08-03-hash-maps.html#updating-a-value-based-on-the-old-value -""" +Learn more in The Book: +https://doc.rust-lang.org/book/ch08-03-hash-maps.html#updating-a-value-based-on-the-old-value""" # QUIZ 2 diff --git a/solutions/11_hashmaps/hashmaps3.rs b/solutions/11_hashmaps/hashmaps3.rs index 4e18198..f4059bb 100644 --- a/solutions/11_hashmaps/hashmaps3.rs +++ b/solutions/11_hashmaps/hashmaps3.rs @@ -1 +1,83 @@ -// Solutions will be available before the stable release. Thank you for testing the beta version 🥰 +// 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 mut 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 mut 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); + } +} |