largest-series-product: Add stub
Since specific errors were just added, stub is provided to help get
student running.
We decided that stubs are a good idea in
We decided that domain-specific errors are a good idea in
+#[derive(Debug, PartialEq)]
+pub enum Error {
+ SpanTooLong,
+ InvalidDigit(char),
+}
+
+pub fn lsp(string_digits: &str, span: usize) -> Result<u64, Error> {
+ unimplemented!("largest series product of a span of {} digits in {}", span, string_digits);
+}
