summaryrefslogtreecommitdiff
path: root/exercises/hashmaps
diff options
context:
space:
mode:
Diffstat (limited to 'exercises/hashmaps')
-rw-r--r--exercises/hashmaps/README.md11
-rw-r--r--exercises/hashmaps/hashmaps1.rs43
-rw-r--r--exercises/hashmaps/hashmaps2.rs80
-rw-r--r--exercises/hashmaps/hashmaps3.rs87
4 files changed, 221 insertions, 0 deletions
diff --git a/exercises/hashmaps/README.md b/exercises/hashmaps/README.md
new file mode 100644
index 0000000..30471cf
--- /dev/null
+++ b/exercises/hashmaps/README.md
@@ -0,0 +1,11 @@
+# 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/exercises/hashmaps/hashmaps1.rs b/exercises/hashmaps/hashmaps1.rs
new file mode 100644
index 0000000..fd8dd2f
--- /dev/null
+++ b/exercises/hashmaps/hashmaps1.rs
@@ -0,0 +1,43 @@
+// hashmaps1.rs
+// 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 three different types of fruits (e.g apple, banana, mango)
+// in the basket and the total count of all the fruits should be at
+// least five.
+//
+// Make me compile and pass the tests!
+//
+// Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+fn fruit_basket() -> HashMap<String, u32> {
+ let mut basket = // TODO: declare your hash map here.
+
+ // Two bananas are already given for you :)
+ basket.insert(String::from("banana"), 2);
+
+ // TODO: Put more fruits in your basket here.
+
+ basket
+}
+
+#[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/exercises/hashmaps/hashmaps2.rs b/exercises/hashmaps/hashmaps2.rs
new file mode 100644
index 0000000..454b3e1
--- /dev/null
+++ b/exercises/hashmaps/hashmaps2.rs
@@ -0,0 +1,80 @@
+// hashmaps2.rs
+
+// A basket of fruits in the form of a hash map is given. 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 *MORE
+// THAN 11* fruits in the basket. Three types of fruits - Apple (4),
+// Mango (2) and Lychee (5) are already given in the basket. You are
+// not allowed to insert any more of these fruits!
+//
+// Make me pass the tests!
+//
+// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+#[derive(Hash, PartialEq, Eq)]
+enum Fruit {
+ Apple,
+ Banana,
+ Mango,
+ Lychee,
+ Pineapple,
+}
+
+fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
+ let fruit_kinds = vec![
+ Fruit::Apple,
+ Fruit::Banana,
+ Fruit::Mango,
+ Fruit::Lychee,
+ Fruit::Pineapple,
+ ];
+
+ for fruit in fruit_kinds {
+ // TODO: Put new fruits if not already present. Note that you
+ // are not allowed to put any type of fruit that's already
+ // present!
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ fn get_fruit_basket() -> HashMap<Fruit, u32> {
+ let mut basket = HashMap::<Fruit, u32>::new();
+ basket.insert(Fruit::Apple, 4);
+ basket.insert(Fruit::Mango, 2);
+ basket.insert(Fruit::Lychee, 5);
+
+ basket
+ }
+
+ #[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);
+ }
+}
diff --git a/exercises/hashmaps/hashmaps3.rs b/exercises/hashmaps/hashmaps3.rs
new file mode 100644
index 0000000..18dd44c
--- /dev/null
+++ b/exercises/hashmaps/hashmaps3.rs
@@ -0,0 +1,87 @@
+// hashmaps3.rs
+
+// 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, goals
+// the team scored, and 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!
+
+// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+// A structure to store team name and its goal details.
+struct Team {
+ name: String,
+ goals_scored: u8,
+ goals_conceded: u8,
+}
+
+fn build_scores_table(results: String) -> HashMap<String, Team> {
+ // The name of the team is the key and its associated struct is the value.
+ let mut scores: HashMap<String, Team> = HashMap::new();
+
+ 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 number of goals conceded from team_2, and similarly
+ // goals scored by team_2 will be the number of goals conceded by
+ // team_1.
+ }
+ scores
+}
+
+#[cfg(test)]
+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
+ }
+
+ #[test]
+ fn build_scores() {
+ let scores = build_scores_table(get_results());
+
+ let mut keys: Vec<&String> = scores.keys().collect();
+ keys.sort();
+ assert_eq!(
+ keys,
+ vec!["England", "France", "Germany", "Italy", "Poland", "Spain"]
+ );
+ }
+
+ #[test]
+ fn validate_team_score_1() {
+ let scores = build_scores_table(get_results());
+ let team = scores.get("England").unwrap();
+ assert_eq!(team.goals_scored, 5);
+ assert_eq!(team.goals_conceded, 4);
+ }
+
+ #[test]
+ fn validate_team_score_2() {
+ let scores = build_scores_table(get_results());
+ let team = scores.get("Spain").unwrap();
+ assert_eq!(team.goals_scored, 0);
+ assert_eq!(team.goals_conceded, 2);
+ }
+}