tasks a-s

Task/Non-continuous-subsequences/D/non-continuous-subsequences-1.d

@@ -0,0 +1,18 @@
+import std.stdio;
+
+T[][] ncsub(T)(in T[] seq, in int s=0) pure nothrow {
+    if (seq.length) {
+        T[][] aux;
+        foreach (ys; ncsub(seq[1..$], s + !(s % 2)))
+            aux ~= seq[0] ~ ys;
+        return aux ~ ncsub(seq[1..$], s + s % 2);
+    } else
+        return new T[][](s >= 3, 0);
+}
+
+void main() {
+    writeln(ncsub([1, 2, 3]));
+    writeln(ncsub([1, 2, 3, 4]));
+    foreach (nc; ncsub([1, 2, 3, 4, 5]))
+        writeln(nc);
+}