Merge remote-tracking branch 'upstream/main' into fix-enum-variant-inconsistency

3 files changed, 220 insertions, 0 deletions

diff --git a/solutions/11_hashmaps/hashmaps1.rs b/solutions/11_hashmaps/hashmaps1.rs
new file mode 100644
index 0000000..3a787c4
--- /dev/null
+++ b/solutions/11_hashmaps/hashmaps1.rs
@@ -0,0 +1,42 @@
+// 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> {
+    // Declare the hash map.
+    let mut basket = HashMap::new();
+
+    // Two bananas are already given for you :)
+    basket.insert(String::from("banana"), 2);
+
+    // Put more fruits in your basket.
+    basket.insert(String::from("apple"), 3);
+    basket.insert(String::from("mango"), 1);
+
+    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/solutions/11_hashmaps/hashmaps2.rs b/solutions/11_hashmaps/hashmaps2.rs
new file mode 100644
index 0000000..a5e6ef9
--- /dev/null
+++ b/solutions/11_hashmaps/hashmaps2.rs
@@ -0,0 +1,95 @@
+// 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 these fruits!
+
+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 {
+        // If fruit doesn't exist, insert it with some value.
+        basket.entry(fruit).or_insert(5);
+    }
+}
+
+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/solutions/11_hashmaps/hashmaps3.rs b/solutions/11_hashmaps/hashmaps3.rs
new file mode 100644
index 0000000..54f480b
--- /dev/null
+++ b/solutions/11_hashmaps/hashmaps3.rs
@@ -0,0 +1,83 @@
+// 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);
+    }
+}