Add small prime divider

src/main.rs

 use num_bigint::BigUint;
 
+mod prime_gen;
+
 fn main() {
-    let max_prime = 20000;
-    let mut sieve = Vec::<Option::<BigUint>>::new();
-    for i in 0..max_prime {
-        sieve.push(Some(BigUint::new(vec![0 as u32])));
-        sieve[i] = match &sieve[i] {
-            Some(n) => Some(n+(i as u32)),
-            None => None
-        }
-    }
-    sieve[0] = None;
-    sieve[1] = None;
-    for i in 2..max_prime {
-        if sieve[i] == None {
-            continue;
-        }
-        let mut k = 2;
-        while i*k < max_prime {
-            sieve[i*k] = None;
-            k += 1;
-        }
-    }
-    let mut p: usize = 0;
-    let mut deleted: bool;
-    while p < sieve.len() {
-        deleted = false;
-        if sieve[p] == None {
-            sieve.remove(p);
-            deleted = true;
-        }
-        p += 1;
-        if deleted {
-            p -= 1;
-        }
-    }
-    for bi in sieve {
-        match bi {
-            None => println!("None"),
-            Some(n) => println!("{}",n)
-        }
+    let n = BigUint::parse_bytes(b"1001692", 10);
+    match n {
+        None => return,
+        Some(m) => println!("{}", prime_gen::divide_small_primes(&m))
     }
 }

src/prime_gen.rs

+use num_bigint::BigUint;
+
+fn erastothenes_sieve(roof: usize) -> Vec::<u64> {
+    let mut sieve = Vec::<u64>::new();
+    for i in 0..roof {
+        sieve.push(i as u64);
+    }
+    sieve[1] = 0;
+    for i in 2..roof {
+        if sieve[i] == 0 {
+            continue;
+        }
+        let mut k = 2;
+        while i*k < roof {
+            sieve[i*k] = 0;
+            k += 1;
+        }
+    }
+    let mut p: usize = 0;
+    let mut deleted: bool;
+    while p < sieve.len() {
+        deleted = false;
+        if sieve[p] == 0 {
+            sieve.remove(p);
+            deleted = true;
+        }
+        if !deleted {
+            p += 1;
+        }
+    }
+    return sieve;
+}
+
+fn divides(b: &BigUint, d: u64) -> bool {
+    let r = b/d;
+    if &(r*d) == b {
+        return true;
+    }
+    return false;
+}
+
+pub fn divide_small_primes(n: &BigUint) -> bool {
+    let small_primes = erastothenes_sieve(20000);
+    for m in small_primes {
+        if divides(n, m) {
+            return false;
+        }
+    }
+    return true;
+}
\ No newline at end of file

target/debug/mental-poker.d

-/home/olavi/mental-poker/target/debug/mental-poker: /home/olavi/mental-poker/src/main.rs /home/olavi/mental-poker/target/debug/build/num-bigint-62520d68e8c7c363/out/radix_bases.rs build.rs
+/home/olavi/mental-poker/target/debug/mental-poker: /home/olavi/mental-poker/src/main.rs /home/olavi/mental-poker/src/prime_gen.rs /home/olavi/mental-poker/target/debug/build/num-bigint-62520d68e8c7c363/out/radix_bases.rs build.rs