Aliquot sequence classifications: Difference between revisions

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      non-terminating: [1488, 2480, 3472, 4464, 8432, 9424, 10416, 21328, 22320, 55056, 95728, 96720, 236592, 459792, 881392, 882384, 1474608]
      non-terminating: [15355717786080, 44534663601120, 144940087464480]
+</pre>
+=={{header|Rust}}==
+<lang rust>#[derive(Debug)]
+enum AliquotType { Terminating, Perfect, Amicable, Sociable, Aspiring, Cyclic, NonTerminating }
+fn classify_aliquot(num: i64) -> (AliquotType, Vec<i64>) {
+    let limit = 1i64 << 47; //140737488355328
+    let mut terms = Some(num).into_iter().collect::<Vec<_>>();
+    for i in 0..16 {
+        let n = terms[i];
+        let divsum = (1..(n + 1) / 2 + 1).filter(|&x| n % x == 0 && n != x).fold(0, |sum, x| sum + x);
+        let classification = if divsum == 0 {
+            Some(AliquotType::Terminating)
+        }
+        else if divsum > limit {
+            Some(AliquotType::NonTerminating)
+        }
+        else if let Some(prev_idx) = terms.iter().position(|&x| x == divsum) {
+            let cycle_len = terms.len() - prev_idx;
+            Some(if prev_idx == 0 {
+                match cycle_len {
+=> AliquotType::Perfect,
+=> AliquotType::Amicable,
+                    _ => AliquotType::Sociable
+                }
+            }
+            else {
+                if cycle_len == 1 {AliquotType::Aspiring} else {AliquotType::Cyclic}
+            })
+        }
+        else {
+            None
+        };
+        terms.push(divsum);
+        if let Some(result) = classification {
+            return (result, terms);
+        }
+    }
+    (AliquotType::NonTerminating, terms)
+}
+fn main() {
+    let nums = [1i64, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 28, 496, 220, 1184, 12496, 1264460, 790, 909, 562, 1064, 1488/*, 15355717786080*/];
+    for num in &nums {
+        println!("{} {:?}", num, classify_aliquot(*num));
+    }
+}</lang>
+{{out}}
+<pre>
+(Terminating, [1, 0])
+(Terminating, [2, 1, 0])
+(Terminating, [3, 1, 0])
+(Terminating, [4, 3, 1, 0])
+(Terminating, [5, 1, 0])
+(Perfect, [6, 6])
+(Terminating, [7, 1, 0])
+(Terminating, [8, 7, 1, 0])
+(Terminating, [9, 4, 3, 1, 0])
+(Terminating, [10, 8, 7, 1, 0])
+(Terminating, [11, 1, 0])
+(Terminating, [12, 16, 15, 9, 4, 3, 1, 0])
+(Perfect, [28, 28])
+(Perfect, [496, 496])
+(Amicable, [220, 284, 220])
+(Amicable, [1184, 1210, 1184])
+(Sociable, [12496, 14288, 15472, 14536, 14264, 12496])
+1264460 (Sociable, [1264460, 1547860, 1727636, 1305184, 1264460])
+(Aspiring, [790, 650, 652, 496, 496])
+(Aspiring, [909, 417, 143, 25, 6, 6])
+(Cyclic, [562, 284, 220, 284])
+(Cyclic, [1064, 1336, 1184, 1210, 1184])
+(NonTerminating, [1488, 2480, 3472, 4464, 8432, 9424, 10416, 21328, 22320, 55056, 95728, 96720, 236592, 459792, 881392, 882384, 1474608])
 </pre>