Sha256: 5bb72da9a6f45faeb89bf33e8f650d5c5c15c974f600e78577560f62b8a9f27b
Contents?: true
Size: 1.77 KB
Versions: 345
Compression:
Stored size: 1.77 KB
Contents
pub type Digit = u32;
///
/// Convert a number between two bases.
///
/// A number is any slice of digits.
/// A digit is any unsigned integer (e.g. u8, u16, u32, u64, or usize).
/// Bases are specified as unsigned integers.
///
/// Return an `Err(.)` if the conversion is impossible.
/// The tests do not test for specific values inside the `Err(.)`.
///
///
/// You are allowed to change the function signature as long as all test still pass.
///
///
/// Example:
/// Input
/// number: &[4, 2]
/// from_base: 10
/// to_base: 2
/// Result
/// Ok(vec![1, 0, 1, 0, 1, 0])
///
/// The example corresponds to converting the number 42 from decimal
/// which is equivalent to 101010 in binary.
///
///
/// Notes:
/// * The empty slice ( "[]" ) is equal to the number 0.
/// * Never output leading 0 digits. However, your function must be able to
/// process input with leading 0 digits.
///
pub fn convert<P: AsRef<[Digit]>>(digits: P, from_base: Digit, to_base: Digit) -> Result<Vec<Digit>, &'static str> {
// check that both bases are in the correct range
if from_base < 2 || to_base < 2 {
return Err("Invalid base");
}
// check that all digits are in the correct range specified by the base
if digits.as_ref().iter().any(|&num| num >= from_base) {
return Err("Digits invalid for input base");
}
// convert all digits into a single large number
let mut immediate = digits.as_ref().iter()
.rev()
.enumerate()
.map(|(i, &num)| num * from_base.pow(i as u32))
.fold(0, |accu, num| accu + num);
// convert number into digits
let mut res = Vec::new();
while immediate > 0 {
res.push(immediate % to_base);
immediate /= to_base;
}
// fix order of digits
res.reverse();
Ok(res)
}
Version data entries
345 entries across 345 versions & 1 rubygems