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-rw-r--r--rustlings/exercises/11_hashmaps/README.md12
-rw-r--r--rustlings/exercises/11_hashmaps/hashmaps1.rs40
-rw-r--r--rustlings/exercises/11_hashmaps/hashmaps2.rs97
-rw-r--r--rustlings/exercises/11_hashmaps/hashmaps3.rs77
4 files changed, 226 insertions, 0 deletions
diff --git a/rustlings/exercises/11_hashmaps/README.md b/rustlings/exercises/11_hashmaps/README.md
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+++ b/rustlings/exercises/11_hashmaps/README.md
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+# Hashmaps
+
+A *hash map* allows you to associate a value with a particular key.
+You may also know this by the names [*unordered map* in C++](https://en.cppreference.com/w/cpp/container/unordered_map),
+[*dictionary* in Python](https://docs.python.org/3/tutorial/datastructures.html#dictionaries) or an *associative array* in other languages.
+
+This is the other data structure that we've been talking about before, when
+talking about Vecs.
+
+## Further information
+
+- [Storing Keys with Associated Values in Hash Maps](https://doc.rust-lang.org/book/ch08-03-hash-maps.html)
diff --git a/rustlings/exercises/11_hashmaps/hashmaps1.rs b/rustlings/exercises/11_hashmaps/hashmaps1.rs
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+// A basket of fruits in the form of a hash map needs to be defined. The key
+// represents the name of the fruit and the value represents how many of that
+// particular fruit is in the basket. You have to put at least 3 different
+// types of fruits (e.g. apple, banana, mango) in the basket and the total count
+// of all the fruits should be at least 5.
+
+use std::collections::HashMap;
+
+fn fruit_basket() -> HashMap<String, u32> {
+ // TODO: Declare the hash map.
+ // let mut basket =
+
+ // Two bananas are already given for you :)
+ basket.insert(String::from("banana"), 2);
+
+ // TODO: Put more fruits in your basket.
+
+ basket
+}
+
+fn main() {
+ // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn at_least_three_types_of_fruits() {
+ let basket = fruit_basket();
+ assert!(basket.len() >= 3);
+ }
+
+ #[test]
+ fn at_least_five_fruits() {
+ let basket = fruit_basket();
+ assert!(basket.values().sum::<u32>() >= 5);
+ }
+}
diff --git a/rustlings/exercises/11_hashmaps/hashmaps2.rs b/rustlings/exercises/11_hashmaps/hashmaps2.rs
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index 0000000..e9f53fe
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+++ b/rustlings/exercises/11_hashmaps/hashmaps2.rs
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+// We're collecting different fruits to bake a delicious fruit cake. For this,
+// we have a basket, which we'll represent in the form of a hash map. The key
+// represents the name of each fruit we collect and the value represents how
+// many of that particular fruit we have collected. Three types of fruits -
+// Apple (4), Mango (2) and Lychee (5) are already in the basket hash map. You
+// must add fruit to the basket so that there is at least one of each kind and
+// more than 11 in total - we have a lot of mouths to feed. You are not allowed
+// to insert any more of the fruits that are already in the basket (Apple,
+// Mango, and Lychee).
+
+use std::collections::HashMap;
+
+#[derive(Hash, PartialEq, Eq, Debug)]
+enum Fruit {
+ Apple,
+ Banana,
+ Mango,
+ Lychee,
+ Pineapple,
+}
+
+fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
+ let fruit_kinds = [
+ Fruit::Apple,
+ Fruit::Banana,
+ Fruit::Mango,
+ Fruit::Lychee,
+ Fruit::Pineapple,
+ ];
+
+ for fruit in fruit_kinds {
+ // TODO: Insert new fruits if they are not already present in the
+ // basket. Note that you are not allowed to put any type of fruit that's
+ // already present!
+ }
+}
+
+fn main() {
+ // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ // Don't modify this function!
+ fn get_fruit_basket() -> HashMap<Fruit, u32> {
+ let content = [(Fruit::Apple, 4), (Fruit::Mango, 2), (Fruit::Lychee, 5)];
+ HashMap::from_iter(content)
+ }
+
+ #[test]
+ fn test_given_fruits_are_not_modified() {
+ let mut basket = get_fruit_basket();
+ fruit_basket(&mut basket);
+ assert_eq!(*basket.get(&Fruit::Apple).unwrap(), 4);
+ assert_eq!(*basket.get(&Fruit::Mango).unwrap(), 2);
+ assert_eq!(*basket.get(&Fruit::Lychee).unwrap(), 5);
+ }
+
+ #[test]
+ fn at_least_five_types_of_fruits() {
+ let mut basket = get_fruit_basket();
+ fruit_basket(&mut basket);
+ let count_fruit_kinds = basket.len();
+ assert!(count_fruit_kinds >= 5);
+ }
+
+ #[test]
+ fn greater_than_eleven_fruits() {
+ let mut basket = get_fruit_basket();
+ fruit_basket(&mut basket);
+ let count = basket.values().sum::<u32>();
+ assert!(count > 11);
+ }
+
+ #[test]
+ fn all_fruit_types_in_basket() {
+ let fruit_kinds = [
+ Fruit::Apple,
+ Fruit::Banana,
+ Fruit::Mango,
+ Fruit::Lychee,
+ Fruit::Pineapple,
+ ];
+
+ let mut basket = get_fruit_basket();
+ fruit_basket(&mut basket);
+
+ for fruit_kind in fruit_kinds {
+ let Some(amount) = basket.get(&fruit_kind) else {
+ panic!("Fruit kind {fruit_kind:?} was not found in basket");
+ };
+ assert!(*amount > 0);
+ }
+ }
+}
diff --git a/rustlings/exercises/11_hashmaps/hashmaps3.rs b/rustlings/exercises/11_hashmaps/hashmaps3.rs
new file mode 100644
index 0000000..5b390ab
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+++ b/rustlings/exercises/11_hashmaps/hashmaps3.rs
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+// 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 TeamScores {
+ goals_scored: u8,
+ goals_conceded: u8,
+}
+
+fn build_scores_table(results: &str) -> HashMap<&str, TeamScores> {
+ // The name of the team is the key and its associated struct is the value.
+ let mut scores = HashMap::<&str, TeamScores>::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();
+
+ // 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
+}
+
+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);
+ }
+}