Data commit

Task/Recamans-sequence/D/recamans-sequence.d

@@ -0,0 +1,39 @@
+import std.stdio;
+
+void main() {
+    int[] a;
+    bool[int] used;
+    bool[int] used1000;
+    bool foundDup;
+
+    a ~= 0;
+    used[0] = true;
+    used1000[0] = true;
+
+    int n = 1;
+    while (n <= 15 || !foundDup || used1000.length < 1001) {
+        int next = a[n - 1] - n;
+        if (next < 1 || (next in used) !is null) {
+            next += 2 * n;
+        }
+        bool alreadyUsed = (next in used) !is null;
+        a ~= next;
+        if (!alreadyUsed) {
+            used[next] = true;
+            if (0 <= next && next <= 1000) {
+                used1000[next] = true;
+            }
+        }
+        if (n == 14) {
+            writeln("The first 15 terms of the Recaman sequence are: ", a);
+        }
+        if (!foundDup && alreadyUsed) {
+            writefln("The first duplicated term is a[%d] = %d", n, next);
+            foundDup = true;
+        }
+        if (used1000.length == 1001) {
+            writefln("Terms up to a[%d] are needed to generate 0 to 1000", n);
+        }
+        n++;
+    }
+}