init

problems/p3/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "p3"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+primal = "0.3.3"

problems/p3/src/main.rs

@@ -0,0 +1,12 @@
+use primal::Sieve;
+
+fn largest_prime_factor(input: u64) -> u64 {
+    let sieve = Sieve::new(1_000_000);
+    let factors = sieve.factor(input as usize).unwrap();
+
+    factors.last().unwrap().0 as u64
+}
+
+fn main() {
+    println!("{}", largest_prime_factor(600851475143));
+}