diff --git a/src/euler56/Cargo.toml b/src/euler56/Cargo.toml new file mode 100644 index 0000000..95e12ba --- /dev/null +++ b/src/euler56/Cargo.toml @@ -0,0 +1,9 @@ +[package] +name = "euler56" +version = "0.1.0" +edition = "2021" + +# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html + +[dependencies] +rug = "1.17.0" diff --git a/src/euler56/src/main.rs b/src/euler56/src/main.rs new file mode 100644 index 0000000..68f4bee --- /dev/null +++ b/src/euler56/src/main.rs @@ -0,0 +1,41 @@ +use rug::{ops::Pow, Integer}; + +fn main() { + let mut solution = vec![]; + for a in 1..100 { + for b in 1..100 { + let aa = Integer::from(a); + let result = digital_sum(aa.pow(b)); + println!("{result}"); + solution.push(result); + } + } + let max = solution.into_iter().max().unwrap(); + println!("{}", max); +} + +fn digital_sum(int: Integer) -> u32 { + int.to_string() + .chars() + .map(|c| c.to_digit(10).unwrap() as u32) + .sum() +} + +#[cfg(test)] +mod test { + use super::digital_sum; + use rug::ops::Pow; + use rug::Integer; + + #[test] + fn test_digital_sum() { + let result = digital_sum(Integer::from(100).pow(100)); + assert_eq!(result, 1); + + let result = digital_sum(Integer::from(5).pow(2)); + assert_eq!(result, 7); + + let result = digital_sum(Integer::from(6).pow(2)); + assert_eq!(result, 9); + } +}