solved 23

src/bin/problem_12.rs

@@ -25,5 +25,9 @@ fn get_divisors(n: usize) -> Vec<usize> {
         }
         potential_divisor = potential_divisor + 1;
     }
+    // This almost made me go mad
+    if potential_divisor * potential_divisor == n {
+        divisors.push(potential_divisor)
+    }
     divisors
 }

src/bin/problem_23.rs

@@ -0,0 +1,64 @@
+use std::cmp::Ordering;
+use crate::NumberType::{Abundant, Deficient, Perfect};
+
+// 4179871
+
+fn main() {
+    let mut abundants = vec![];
+    let mut sum = 0;
+    let upper_bound = 28123;
+    for num in 1..=upper_bound {
+        let num_type = get_number_type(num);
+        if num_type == Abundant {
+            abundants.push(num);
+        }
+        let mut contained = false;
+        for abundant in &abundants {
+            match abundants.binary_search(&(num-abundant)) {
+                Ok(_) => {
+                    contained = true;
+                    break;
+                }
+                Err(_) => {}
+            }
+        }
+        if !contained {
+            sum += num;
+        }
+    }
+    //println!("{:?}", abundants);
+    println!("{sum}");
+}
+
+#[derive(Eq, PartialEq)]
+enum NumberType {
+    Perfect,
+    Deficient,
+    Abundant,
+}
+
+fn get_number_type(n: usize) -> NumberType {
+    let divisor_sum = get_divisors(n).iter().sum::<usize>();
+    match divisor_sum.cmp(&n) {
+        Ordering::Equal => Perfect,
+        Ordering::Less => Deficient,
+        Ordering::Greater => Abundant,
+    }
+}
+
+fn get_divisors(n: usize) -> Vec<usize> {
+    let mut divisors = vec![1];
+    let mut potential_divisor = 2;
+    while (potential_divisor * potential_divisor) < n {
+        if n % potential_divisor == 0 {
+            divisors.push(potential_divisor);
+            divisors.push(n / potential_divisor);
+        }
+        potential_divisor = potential_divisor + 1;
+    }
+    // This almost made me go mad, should have used the one from 21
+    if potential_divisor * potential_divisor == n {
+        divisors.push(potential_divisor)
+    }
+    divisors
+}