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Cheryl's birthday: Difference between revisions
Add Rust implementation
m (→{{header|Sidef}}: updated code to use the built-in Date class) |
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3 remaining
["July", 16]</pre>
=={{header|Rust}}==
<lang rust>
// This version is based on the Go version on Rosettacode
#[derive(PartialEq, Debug, Copy, Clone)]
enum Month {
May,
June,
July,
August,
}
#[derive(PartialEq, Debug, Copy, Clone)]
struct Birthday {
month: Month,
day: u8,
}
impl Birthday {
fn month_unique_in(&self, birthdays: &[Birthday]) -> bool {
birthdays
.iter()
.filter(|birthday| birthday.month == self.month)
.count()
== 1
}
fn day_unique_in(&self, birthdays: &[Birthday]) -> bool {
birthdays
.iter()
.filter(|birthday| birthday.day == self.day)
.count()
== 1
}
fn month_with_unique_day_in(&self, birthdays: &[Birthday]) -> bool {
birthdays
.iter()
.any(|birthday| self.month == birthday.month && birthday.day_unique_in(birthdays))
}
}
fn solution() -> Option<Birthday> {
let mut choices: Vec<Birthday> = vec![
Birthday {
month: Month::May,
day: 15,
},
Birthday {
month: Month::May,
day: 16,
},
Birthday {
month: Month::May,
day: 19,
},
Birthday {
month: Month::June,
day: 17,
},
Birthday {
month: Month::June,
day: 18,
},
Birthday {
month: Month::July,
day: 14,
},
Birthday {
month: Month::July,
day: 16,
},
Birthday {
month: Month::August,
day: 14,
},
Birthday {
month: Month::August,
day: 15,
},
Birthday {
month: Month::August,
day: 17,
},
];
// Albert knows the month but doesn't know the day.
// So the month can't be unique within the choices.
let choices_copy = choices.clone();
choices.retain(|birthday| !(&birthday.month_unique_in(&choices_copy)));
// Albert also knows that Bernard doesn't know the answer.
// So the month can't have a unique day.
let choices_copy = choices.clone();
choices.retain(|birthday| !(birthday.month_with_unique_day_in(&choices_copy)));
// Bernard now knows the answer.
// So the day must be unique within the remaining choices.
let choices_copy = choices.clone();
choices.retain(|birthday| birthday.day_unique_in(&choices_copy));
// Albert now knows the answer too.
// So the month must be unique within the remaining choices.
let choices_copy = choices.clone();
choices.retain(|birthday| birthday.month_unique_in(&choices_copy));
if choices.len() == 1 {
Some(choices[0])
} else {
None
}
}
fn main() {
match solution() {
Some(solution) => println!("Cheryl's birthday is {:?}", solution),
None => panic!("Didn't work!"),
}
}
</lang>
{{out}}
<pre>
Cheryl's birthday is Birthday { month: July, day: 16 }
</pre>
=={{header|Scala}}==
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