Data commit

Task/Perfect-numbers/D/perfect-numbers-1.d

@@ -0,0 +1,12 @@
+import std.stdio, std.algorithm, std.range;
+
+bool isPerfectNumber1(in uint n) pure nothrow
+in {
+    assert(n > 0);
+} body {
+    return n == iota(1, n - 1).filter!(i => n % i == 0).sum;
+}
+
+void main() {
+    iota(1, 10_000).filter!isPerfectNumber1.writeln;
+}

Task/Perfect-numbers/D/perfect-numbers-2.d

@@ -0,0 +1,21 @@
+import std.stdio, std.math, std.range, std.algorithm;
+
+bool isPerfectNumber2(in int n) pure nothrow {
+    if (n < 2)
+        return false;
+
+    int total = 1;
+    foreach (immutable i; 2 .. cast(int)real(n).sqrt + 1)
+        if (n % i == 0) {
+            immutable int q = n / i;
+            total += i;
+            if (q > i)
+                total += q;
+        }
+
+    return total == n;
+}
+
+void main() {
+    10_000.iota.filter!isPerfectNumber2.writeln;
+}