feat: Add hashmap3 exercise.

This commit is contained in:
Sateesh Basavaraju 2021-06-04 16:09:12 +05:30 committed by mokou
parent fe54d0f85b
commit 1e54bc61e8
2 changed files with 100 additions and 0 deletions

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@ -0,0 +1,88 @@
// 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 the command `rustlings hint hashmap3` if you need
// hints.
// 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);
}
}

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@ -506,6 +506,18 @@ Use the `entry()` and `or_insert()` methods of `HashMap` to achieve this.
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
"""
[[exercises]]
name = "hashmaps3"
path = "exercises/hashmaps/hashmaps3.rs"
mode = "test"
hint = """
Hint 1: Use the `entry()` and `or_insert()` methods of `HashMap` to insert entries corresponding to each team in the scores table.
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
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
"""
# TEST 2
[[exercises]]