feat: add get_factors to pre-algebra unit1.rs

ladderz/src/lib.rs

@@ -1,4 +1,4 @@
-//! Non-production implementations of mathematical and technical concepts in Rust.
+//! Implementations of mathematical and technical concepts in Rust.
 
 /// Various pre-algebra implementations including multiples (planned), factor pairs, etc.
 pub mod pre_algebra;

ladderz/src/pre_algebra/unit1.rs

@@ -1,6 +1,13 @@
 use std::collections::HashSet;
 
-// TODO: Implement negative integers
+/// Finds all factor pairs for a given positive integer.
+/// 
+/// # Challenge
+/// 
+/// Write a program that finds all the factor pairs for a given number `n`.
+/// 
+/// # Description
+/// 
 /// Generates a `HashSet` of factor pairs for a given positive integer `n`.
 ///
 /// This function calculates and returns a `HashSet` containing all unique factor pairs
@@ -50,14 +57,80 @@ pub fn get_factor_pairs(n: u32) -> HashSet<(u32, u32)> {
     factor_pairs
 }
 
+/// Finds all factors of a given positive integer.
+/// 
+/// # Challenge
+/// 
+/// Write a program that finds all the factors of a given number. Assume that `n` is a positive integer greater than or equal to 1.
+///
+/// # Description
+/// 
+/// Generates a `HashSet` of factors for a given positive integer `n`.
+///
+/// This function calculates and returns a `HashSet` containing all unique factors
+/// of the input positive integer `n`. A factor of `n` is a positive integer `a` where
+/// `n` is evenly divisible by `a` (i.e., `n % a == 0`).
+///
+/// # Arguments
+///
+/// * `n` - The positive integer for which factors are to be calculated.
+///
+/// # Returns
+///
+/// A `HashSet` containing all unique factors of the input integer `n`.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::collections::HashSet;
+/// use ladderz::pre_algebra::unit1::get_factors;
+///
+/// fn main() {
+///     let result_factors = get_factors(16);
+///     let expected_factors: HashSet<u32> = [1, 2, 4, 8, 16].into();
+///     assert_eq!(result_factors, expected_factors);
+/// }
+/// ```
+///
+/// # Note
+///
+/// This function calculates factors by iterating through positive integers from 1 to `n`
+/// (inclusive) and checking if they divide `n` evenly. If they do, the factor is added to
+/// the `HashSet`. The function ensures that factors are unique, so duplicates are not added.
+pub fn get_factors(n: u32) -> HashSet<u32> {
+    let mut factors: HashSet<u32> = HashSet::new();
+
+    for num in 1..n+1 {
+        if n % num == 0 {
+            factors.insert(num);
+        }
+    }
+    factors
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
-    fn test_get_factor_pairs_1() {
+    fn test_get_factor_pairs() {
         let result: HashSet<(u32, u32)> = get_factor_pairs(1);
         let expected: HashSet<(u32, u32)> = [(1, 1)].into();
         assert_eq!(result, expected);
+
+        let result_2: HashSet<(u32, u32)> = get_factor_pairs(16);
+        let expected_2: HashSet<(u32, u32)> = [(1, 16), (2, 8), (4, 4)].into();
+        assert_eq!(result_2, expected_2);
+    }
+
+    #[test]
+    fn test_get_factors() {
+        let result: HashSet<u32> = get_factors(1);
+        let expected: HashSet<u32> = [1].into();
+        assert_eq!(result, expected);
+
+        let result_2: HashSet<u32> = get_factors(16);
+        let expected_2: HashSet<u32> = [1, 2, 4, 8, 16].into();
+        assert_eq!(result_2, expected_2);
     }
 }