Data commit

Task/Fibonacci-sequence/PL-pgSQL/fibonacci-sequence-1.sql

@@ -0,0 +1,8 @@
+CREATE OR REPLACE FUNCTION fib(n INTEGER) RETURNS INTEGER AS $$
+BEGIN
+  IF (n < 2) THEN
+    RETURN n;
+  END IF;
+  RETURN fib(n - 1) + fib(n - 2);
+END;
+$$ LANGUAGE plpgsql;

Task/Fibonacci-sequence/PL-pgSQL/fibonacci-sequence-2.sql

@@ -0,0 +1,5 @@
+CREATE OR REPLACE FUNCTION fibFormula(n INTEGER) RETURNS INTEGER AS $$
+BEGIN
+  RETURN round(pow((pow(5, .5) + 1) / 2, n) / pow(5, .5));
+END;
+$$ LANGUAGE plpgsql;

Task/Fibonacci-sequence/PL-pgSQL/fibonacci-sequence-3.sql

@@ -0,0 +1,17 @@
+CREATE OR REPLACE FUNCTION fibLinear(n INTEGER) RETURNS INTEGER AS $$
+DECLARE
+  prevFib INTEGER := 0;
+  fib INTEGER := 1;
+BEGIN
+  IF (n < 2) THEN
+    RETURN n;
+  END IF;
+
+  WHILE n > 1 LOOP
+    SELECT fib, prevFib + fib INTO prevFib, fib;
+    n := n - 1;
+  END LOOP;
+
+  RETURN fib;
+END;
+$$ LANGUAGE plpgsql;

Task/Fibonacci-sequence/PL-pgSQL/fibonacci-sequence-4.sql

@@ -0,0 +1,9 @@
+CREATE OR REPLACE FUNCTION fibTailRecursive(n INTEGER, prevFib INTEGER DEFAULT 0, fib INTEGER DEFAULT 1)
+RETURNS INTEGER AS $$
+BEGIN
+  IF (n = 0) THEN
+    RETURN prevFib;
+  END IF;
+  RETURN fibTailRecursive(n - 1, fib, prevFib + fib);
+END;
+$$ LANGUAGE plpgsql;