day08 done.

aoc_libs/src/lib.rs

@@ -1,2 +1,3 @@
 pub mod points;
 pub mod range;
+pub mod misc;

aoc_libs/src/misc.rs

@@ -0,0 +1,43 @@
+pub fn arr_lcm(input: &[usize]) -> usize {
+    input.iter().copied().reduce(lcm).unwrap_or(0)
+}
+
+pub fn lcm(first: usize, second: usize) -> usize {
+    first * second / gcd(&first, &second)
+}
+
+pub fn gcd(a: &usize, b: &usize) -> usize {
+    let mut a = *a;
+    let mut b = *b;
+    while b != 0 {
+        let tmp = b;
+        b = a.rem_euclid(b);
+        a = tmp;
+    }
+    a
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_arr_lcm() {
+        assert_eq!(arr_lcm(&[4, 6]), 12);
+        assert_eq!(arr_lcm(&[5, 2]), 10);
+        assert_eq!(arr_lcm(&[5, 2, 6]), 30);
+        assert_eq!(arr_lcm(&[5, 2, 6, 3]), 30);
+    }
+
+    #[test]
+    fn test_lcm() {
+        assert_eq!(lcm(4, 6), 12);
+        assert_eq!(lcm(5, 2), 10);
+    }
+
+    #[test]
+    fn test_gcd() {
+        assert_eq!(gcd(&8, &12), 4);
+        assert_eq!(gcd(&54, &24), 6);
+    }
+}