Hofstadter Q sequence: Difference between revisions

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@@ Line 448: / Line 448: @@
 <lang d>import std.stdio, std.algorithm, std.range, std.array;
+uint Q(in int n) nothrow
-struct Q {
+in {
-    __gshared static Appender!(uint[]) s;
+    assert(n > 0);
+} body {
+    __gshared static Appender!(int[]) s = [0, 1, 1];
+    foreach (immutable i; s.data.length .. n + 1)
-    nothrow static this() {
-        s ~= [0, 1, 1];
+        s ~= s.data[i - s.data[i - 1]] + s.data[i - s.data[i - 2]];
+    return s.data[n];
-    }
-    static uint opCall(in int n) nothrow
-    in {
-        assert(n > 0);
-    } body {
-        foreach (immutable i; s.data.length .. n + 1)
-            s ~= s.data[i - s.data[i - 1]] + s.data[i - s.data[i - 2]];
-        return s.data[n];
-    }
 }