Merging local with remote main

48 files changed, 1045 insertions, 5 deletions

diff --git a/entries/MarieSal0/FibonacciWorkplace/.gitignore b/entries/MarieSal0/FibonacciWorkplace/.gitignore
new file mode 100644
index 0000000..9b956f9
--- /dev/null
+++ b/entries/MarieSal0/FibonacciWorkplace/.gitignore
@@ -0,0 +1,133 @@
+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+
+# User-specific files
+*.suo
+*.user
+*.sln.docstates
+
+# Build results
+
+[Dd]ebug/
+[Rr]elease/
+x64/
+[Bb]in/
+[Oo]bj/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+*_i.c
+*_p.c
+*_i.h
+*.ilk
+*.meta
+*.obj
+*.pch
+*.pdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*.log
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.log
+*.svclog
+*.scc
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opensdf
+*.sdf
+*.cachefile
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.Publish.xml
+*.pubxml
+*.azurePubxml
+
+# NuGet Packages Directory
+## TODO: If you have NuGet Package Restore enabled, uncomment the next line
+packages/
+## TODO: If the tool you use requires repositories.config, also uncomment the next line
+!packages/repositories.config
+
+# Windows Azure Build Output
+csx/
+*.build.csdef
+
+# Windows Store app package directory
+AppPackages/
+
+# Others
+sql/
+*.Cache
+ClientBin/
+[Ss]tyle[Cc]op.*
+![Ss]tyle[Cc]op.targets
+~$*
+*~
+*.dbmdl
+*.[Pp]ublish.xml
+
+*.publishsettings
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file to a newer
+# Visual Studio version. Backup files are not needed, because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+
+# SQL Server files
+App_Data/*.mdf
+App_Data/*.ldf
+
+# =========================
+# Windows detritus
+# =========================
+
+# Windows image file caches
+Thumbs.db
+ehthumbs.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Mac desktop service store files
+.DS_Store
+
+_NCrunch*
\ No newline at end of file
diff --git a/entries/MarieSal0/FibonacciWorkplace/FibonacciWorkplace.csproj b/entries/MarieSal0/FibonacciWorkplace/FibonacciWorkplace.csproj
new file mode 100644
index 0000000..40c60dd
--- /dev/null
+++ b/entries/MarieSal0/FibonacciWorkplace/FibonacciWorkplace.csproj
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">

+

+  <PropertyGroup>

+    <OutputType>Exe</OutputType>

+    <TargetFramework>net6.0</TargetFramework>

+    <ImplicitUsings>enable</ImplicitUsings>

+    <Nullable>enable</Nullable>

+  </PropertyGroup>

+

+</Project>

diff --git a/entries/MarieSal0/FibonacciWorkplace/Program.cs b/entries/MarieSal0/FibonacciWorkplace/Program.cs
new file mode 100644
index 0000000..bac5688
--- /dev/null
+++ b/entries/MarieSal0/FibonacciWorkplace/Program.cs
@@ -0,0 +1,41 @@
+using System; 

+namespace FibonacciWorkplace

+{

+    public class Program

+    {

+        static void Main(string[] args)

+        {

+            Console.Write("How long should the Fibonacci Series be?? ");

+            int lengthOfSeries = Convert.ToInt32(Console.ReadLine());

+            if (lengthOfSeries<=2)

+            {

+                LengthCheck(lengthOfSeries);

+            }

+            FibonacciSeries(0, 1, 1, lengthOfSeries);

+            Console.ReadKey();

+        }

+        public static void LengthCheck(int lengthOfSeries)

+        {

+            if (lengthOfSeries<=1)

+            {

+                Console.Write("The Fibonacci Series needs to be greater than 2");

+                lengthOfSeries = Convert.ToInt32(Console.ReadLine());     

+                LengthCheck(lengthOfSeries);      

+            }

+                

+        }

+        

+        public static void FibonacciSeries(int firstNumber, int secondNumber, int counter, int lengthOfSeries)

+        {

+            Console.Write(firstNumber + " ");

+            if (counter < lengthOfSeries)

+            {

+                int sum = firstNumber + secondNumber; 

+                counter++;

+                FibonacciSeries(secondNumber, sum, counter, lengthOfSeries);

+            }

+        }

+

+        

+    }

+}
\ No newline at end of file
diff --git a/entries/Metroxe/index.html b/entries/Metroxe/index.html
index 98ac5b9..cb85a24 100644
--- a/entries/Metroxe/index.html
+++ b/entries/Metroxe/index.html
@@ -23,7 +23,7 @@
     const n1 = s.substring(i1 + 1);
     const n2 = i2 === -1 ? s.substring(0, i1 - 1) : s.substring(i2 + 1, i1);
     const v = Number(n1) + Number(n2);
-    const output = `${s},${Number(n1) + Number(n2)}`;
+    const output = `${s},${v}`;
     document.getElementById("sequence").innerText = output;
 
     const next = document.getElementById("next");
diff --git a/entries/StuartLiv/ThetaFibN.java b/entries/StuartLiv/ThetaFibN.java
new file mode 100644
index 0000000..1e4f431
--- /dev/null
+++ b/entries/StuartLiv/ThetaFibN.java
@@ -0,0 +1,13 @@
+public class ThetaFibN {
+
+	//Fibonacci(n) is asymptotically in ϴ(Fibonacci(n))
+	public int Fibonacci(int n) {
+		String reference = "0";
+		int fib = 1;
+		for(int i = 1; i <= n; i++) {
+			fib = reference.length();
+			reference = reference.replace("0", "").replace("1", "0") + "1".repeat(fib);
+		}
+		return fib;
+	}
+}
diff --git a/entries/Tarcisio-Teixeira/fib.py b/entries/Tarcisio-Teixeira/fib.py
new file mode 100644
index 0000000..a73cdd2
--- /dev/null
+++ b/entries/Tarcisio-Teixeira/fib.py
@@ -0,0 +1,5 @@
+def fib(n,arr={},v =-1):
+    if v>=0:
+        arr[n]=v
+        return v
+    return arr[n] if n in arr.keys() else fib(n, arr, (2*n*n*n - 9*n*n+13*n)//6 if  n <= 3 else fib(n//2-1,arr)*fib(n-n//2,arr) + fib(n//2,arr)*fib(n-n//2+1,arr))
diff --git a/entries/adirar111/wasm/fib.wasm b/entries/adirar111/wasm/fib.wasm
new file mode 100644
index 0000000..6a93250
--- /dev/null
+++ b/entries/adirar111/wasm/fib.wasm
diff --git a/entries/adirar111/wasm/fib.wat b/entries/adirar111/wasm/fib.wat
new file mode 100644
index 0000000..255fa12
--- /dev/null
+++ b/entries/adirar111/wasm/fib.wat
@@ -0,0 +1,46 @@
+;; iterative fib(n) in web assembly text format (wat)
+;; this gets compiled to the fib.wasm binary
+;; and gets fetched via a data URL in index.js
+(module
+	(export "fib" (func $fib))
+	(func $fib (param $n i32) (result i32)
+	(local $last i32)
+	(local $sum i32)
+	(local $i i32)
+	(local $tmp i32)
+	(if
+		(i32.lt_s
+			(local.get $n)
+			(i32.const 2)
+		)
+		(return (local.get $n))
+	)
+	(local.set $last (i32.const 0))
+	(local.set $sum (i32.const 1))
+	(local.set $i (i32.const 2))
+	(local.set $n (i32.add (local.get $n) (i32.const 1)))
+	(loop $loop
+		(local.set $tmp (local.get $sum))
+		(local.set $sum
+			(i32.add
+				(local.get $sum)
+				(local.get $last)
+			)
+		)
+		(local.set $last (local.get $tmp))
+		(local.set $i
+			(i32.add
+				(local.get $i)
+				(i32.const 1)
+			)
+		)
+		(br_if $loop
+			(i32.lt_s
+				(local.get $i)
+				(local.get $n)
+			)
+		)
+	)
+	(return (local.get $sum))
+	)
+)
diff --git a/entries/adirar111/wasm/index.html b/entries/adirar111/wasm/index.html
new file mode 100644
index 0000000..8357a55
--- /dev/null
+++ b/entries/adirar111/wasm/index.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>wasm fib</title>
+		<link
+			href="https://fonts.googleapis.com/css2?family=Source+Code+Pro:wght@600;700&display=swap"
+			rel="stylesheet"
+		/>
+		<link rel="stylesheet" href="style.css" />
+	</head>
+	<body>
+		<p>go ahead, type a number</p>
+		<div id="input-area">
+			<input id="input" type="text" autocomplete="off" />
+			<button id="compute">compute!</button>
+		</div>
+		<p>fib.wasm says:</p>
+		<span id="result"></span>
+		<script src="index.js"></script>
+	</body>
+</html>
diff --git a/entries/adirar111/wasm/index.js b/entries/adirar111/wasm/index.js
new file mode 100644
index 0000000..667ff82
--- /dev/null
+++ b/entries/adirar111/wasm/index.js
@@ -0,0 +1,23 @@
+const wasmBinaryBase64 = "AGFzbQEAAAABBgFgAX8BfwMCAQAHBwEDZmliAAAKRwFFAQR/IABBAkgEQCAADwtBACEBQQEhAkECIQMgAEEBaiEAA0AgAiEEIAIgAWohAiAEIQEgA0EBaiEDIAMgAEgNAAsgAg8LACgEbmFtZQEGAQADZmliAhkBAAUAAW4BBGxhc3QCA3N1bQMBaQQDdG1w"
+const wasmBinaryDataURL = `data:application/wasm;base64,${wasmBinaryBase64}`;
+
+WebAssembly.instantiateStreaming(fetch(wasmBinaryDataURL)).then(
+	(wasmObj) => {
+		const {fib: fibWasm} = wasmObj.instance.exports
+		const fib = (event) => {
+			event.preventDefault()
+			const input = document.getElementById("input")
+			const result = document.getElementById("result")
+			const n = parseInt(input.value)
+			if (isNaN(n)) {
+				return result.textContent = "that wasn't very wasm of you"
+			}
+			if (n < 0) {
+				return result.textContent = "why are you being so negative"
+			}
+			result.textContent = fibWasm(n)
+		}
+		const button = document.getElementById("compute")
+		button.onclick = fib
+	}
+);
diff --git a/entries/adirar111/wasm/style.css b/entries/adirar111/wasm/style.css
new file mode 100644
index 0000000..8ab403f
--- /dev/null
+++ b/entries/adirar111/wasm/style.css
@@ -0,0 +1,27 @@
+html {
+	background: #5a46ee;
+	color: #fff;
+	font-family: "Source Code Pro"
+}
+
+body {
+	display: flex;
+	flex-direction: column;
+	justify-content: center;
+	align-items: center;
+}
+
+#input-area {
+	display: flex;
+	flex-direction: row;
+	justify-content: space-between;
+}
+
+#input {
+	height: 40px;
+	font-size: 30px
+}
+
+#result {
+	font-size: 50px
+}
diff --git a/entries/adirar111/y86/fib.ys b/entries/adirar111/y86/fib.s
index 156c1ae..8aa62d2 100644
--- a/entries/adirar111/y86/fib.ys
+++ b/entries/adirar111/y86/fib.s
@@ -1,8 +1,13 @@
 # y86 implementation of
+#
 # def fibonacci(n):
-# if n <= 1:
-# return n
-# return fibonacci(n-1) + fibonacci(n-2)
+#     if n <= 1:
+#         return n
+#     return fibonacci(n-1) + fibonacci(n-2)
+#
+# run it:
+#  * https://www.students.cs.ubc.ca/~cs-313/simulator/?arch=y86&impl=seq
+#  * https://www.eecs.yorku.ca/~jonatan/simulator/?arch=y86&impl=seq
 
 .pos 0
 main:
diff --git a/entries/fbanados/fib.st b/entries/fbanados/fib.st
new file mode 100644
index 0000000..099407c
--- /dev/null
+++ b/entries/fbanados/fib.st
@@ -0,0 +1,8 @@
+'From Pharo10.0.0 of 15 June 2022 [Build information: Pharo-10.0.0+build.521.sha.14f541319d443f4261f84f4fa19fbb34460a5edb (64 Bit)] on 24 October 2022 at 11:26:20.436554 am'!
+
+!Integer methodsFor: '*Fibonacci' stamp: 'FelipeBanados 10/24/2022 11:13'!
+fibonacciNumber
+	self <= 2 ifTrue: [ ^ 1 ].
+	^ (self - 1) fibonacciNumber + (self - 2) fibonacciNumber.
+
+! !
diff --git a/entries/fbanados/fib.v b/entries/fbanados/fib.v
new file mode 100644
index 0000000..e9fe796
--- /dev/null
+++ b/entries/fbanados/fib.v
@@ -0,0 +1,90 @@
+Require Import Coq.Arith.Wf_nat. (* import strong induction on naturals *)
+Require Import Lia. (* Linear Integer Arithmetic solver *)
+
+(* First, simple specification *)
+
+Fixpoint fib_simpl (n : nat) {struct n} : nat :=
+  match n with
+  | 0 => 1
+  | S n => match n with
+           | 0 => 1
+           | S m => fib_simpl n + fib_simpl m
+           end
+  end.
+
+Example fib_3 : (fib_simpl 2 = 2). reflexivity. Qed.
+Example fib_4 : (fib_simpl 3 = 3). reflexivity. Qed.
+Example fib_5 : (fib_simpl 4 = 5). reflexivity. Qed.
+
+Lemma fib_simpl_spec : forall n, (* useful lemma for rewriting *)
+    fib_simpl (S (S n)) = fib_simpl (S n) + fib_simpl n.
+Proof.
+  destruct n.
+  - (* case n := 0 *)
+    reflexivity.
+  - (* case n := (S n) *)
+    destruct n; reflexivity.
+Qed.
+      
+(* For a (slightly) faster version *)
+
+Fixpoint fib_acc_aux (n : nat) (acc : nat) (prev : nat) {struct n} : nat :=
+  match n with
+  | 0 => acc + prev
+  | S n => fib_acc_aux n (acc + prev) acc
+  end.
+
+Definition fib_faster (n : nat) : nat :=
+  match n with
+  | 0 => 1
+  | S n => match n with
+           | 0 => 1
+           | S m => (fib_acc_aux m 1 1)
+           end
+  end.
+
+Example fib_faster_3 : (fib_faster 2 = 2). reflexivity. Qed.
+Example fib_faster_4 : (fib_faster 3 = 3). reflexivity. Qed.
+Example fib_faster_5 : (fib_faster 4 = 5). reflexivity. Qed.
+
+Lemma fib_acc_aux_rewrite : forall n a b c d,
+    fib_acc_aux n a c + fib_acc_aux n b d = fib_acc_aux n (a + b) (c + d).
+Proof.
+  induction n; intros.
+  - (* case n := 0 *)
+    simpl; lia.
+  - (* case n := (S n) *)
+    simpl.
+    rewrite IHn.
+    f_equal.
+    lia.
+Qed.    
+  
+Theorem fib_faster_spec: forall n, fib_simpl n = fib_faster n.
+Proof.
+  induction n using lt_wf_ind. (* use strong induction *)
+  rename H into strong_induction_hypothesis.
+  destruct n. (* lt_wf_ind does not deal immediately with cases *)
+  - (* case n := 0 *)
+    reflexivity.
+  - (* case n := (S n) *)
+    destruct n.
+    + (* case n := 1 *)
+      reflexivity.
+    + (* case n := (S (S n)) *)
+      rewrite ?fib_simpl_spec.
+      do 2 rewrite strong_induction_hypothesis by lia.
+      enough (forall n, fib_faster (S n) + fib_faster n = fib_faster (S (S n))) as lemma by apply lemma.
+      clear.
+      destruct n.
+      * (* for lemma, case n := 0 *)
+        reflexivity.
+      * (* for lemma, case n := S n *)
+        destruct n.
+        -- (* for lemma, case n := 1 *)
+          reflexivity.
+        -- (* for lemma, case n := S (S n) *)
+           simpl. 
+           apply fib_acc_aux_rewrite.
+Qed.
+
diff --git a/entries/funemy/.gitignore b/entries/funemy/.gitignore
new file mode 100644
index 0000000..acb903a
--- /dev/null
+++ b/entries/funemy/.gitignore
@@ -0,0 +1,3 @@
+.DS_Store
+*.agdai
+*.smt2
diff --git a/entries/funemy/agda/fib1.agda b/entries/funemy/agda/fib1.agda
new file mode 100644
index 0000000..d8931a0
--- /dev/null
+++ b/entries/funemy/agda/fib1.agda
@@ -0,0 +1,34 @@
+open import Agda.Builtin.Equality
+
+data Nat : Set where
+  zero : Nat
+  suc : Nat -> Nat
+
+{-# BUILTIN NATURAL Nat #-}
+
+z : Nat
+z = zero
+
+one : Nat
+one = suc zero
+
+add : Nat → Nat → Nat
+add zero y = y
+add (suc x) y = suc (add x y)
+
+fib : Nat → Nat
+fib zero = zero
+fib (suc zero) = suc zero
+fib (suc (suc x)) = add (fib x) (fib (suc x))
+
+fib0 : fib 0 ≡ 0
+fib0 = refl
+
+fib1 : fib 1 ≡ 1
+fib1 = refl
+
+fib2 : fib 2 ≡ 1
+fib2 = refl
+
+fib8 : fib 8 ≡ 21
+fib8 = refl
diff --git a/entries/funemy/z3/z3fib.sh b/entries/funemy/z3/z3fib.sh
new file mode 100755
index 0000000..07ab418
--- /dev/null
+++ b/entries/funemy/z3/z3fib.sh
@@ -0,0 +1,57 @@
+#!/bin/bash
+
+# Instructions:
+#  1. having z3 installed and put under your $PATH
+#  2. making sure z3fib.sh is executable, by `chmod +x z3fib.sh`
+#  3. running as `./z3fib.sh [length of the fib sequence]`
+#  4. having fun :)
+
+if [ -e fib.smt2 ]
+then
+    rm -f fib.smt2
+    touch fib.smt2
+else
+    touch fib.smt2
+fi
+
+if [ "$1" -lt "0" ]; then
+  echo "Argument must be larger than 0."
+  exit 1
+fi
+
+for i in $(seq 0 $1);
+do
+  echo "(declare-const x$i Int)" >> fib.smt2
+done
+
+echo "" >> fib.smt2
+
+echo "(assert" >> fib.smt2
+echo "  (and" >> fib.smt2
+
+for i in $(seq 0 $1);
+do
+  echo "    (>= x$i 0)" >> fib.smt2
+done
+
+echo "    (= x0 0)" >> fib.smt2
+if [ "$1" -ge "1" ]; then
+  echo "    (= x1 1)" >> fib.smt2
+fi
+
+if [ "$1" -ge "2" ]; then
+  for i in $(seq 2 $1);
+  do
+    echo "    (= x$i (+ x$(($i - 2)) x$(($i - 1))))" >> fib.smt2
+  done
+fi
+
+echo "  )" >> fib.smt2
+echo ")" >> fib.smt2
+
+echo "" >> fib.smt2
+
+echo "(check-sat)" >> fib.smt2
+echo "(get-model)" >> fib.smt2
+
+z3 fib.smt2
diff --git a/entries/ionathanch/Fib.agda b/entries/ionathanch/Fib.agda
new file mode 100644
index 0000000..a12b0a5
--- /dev/null
+++ b/entries/ionathanch/Fib.agda
@@ -0,0 +1,19 @@
+
+open import Agda.Builtin.Nat
+open import Agda.Builtin.List
+open import Agda.Builtin.Reflection
+
+data Fib : Nat → Nat → Set where
+  instance F0 : Fib 0 0
+  instance F1 : Fib 1 1
+  instance Fk : ∀ {k n m} → ⦃ Fib k n ⦄ → ⦃ Fib (suc k) m ⦄ → Fib (suc (suc k)) (n + m)
+
+fib' : ∀ k {n} → ⦃ Fib k n ⦄ → Nat
+fib' k {n} ⦃ fib ⦄ = n
+
+macro
+  fib : Term → Term → TC _
+  fib t hole = unify hole (def (quote fib') (arg i t ∷ []))
+    where i = arg-info visible (modality relevant quantity-ω)
+
+{- Get the [n]th Fibonacci number by normalization via C-n `fib [n]`. -}
diff --git a/entries/ionathanch/fib.f90 b/entries/ionathanch/fib.f90
new file mode 100644
index 0000000..3cf1850
--- /dev/null
+++ b/entries/ionathanch/fib.f90
@@ -0,0 +1,21 @@
+PROGRAM main
+  ! The 93rd Fibonacci number is the largest that fits in 64 bits anyway
+  CHARACTER(3) :: kth
+  INTEGER :: k
+  CALL get_command_argument(1, kth)
+  READ(kth, *) k
+  WRITE(*, *) fib(k)
+CONTAINS
+
+PURE RECURSIVE INTEGER*8 FUNCTION fib(k) RESULT(n)
+  INTEGER, INTENT (IN) :: k
+  IF (k == 0) THEN
+    n = 0
+  ELSE IF (k == 1) THEN
+    n = 1
+  ELSE
+    n = fib(k - 1) + fib(k - 2)
+  END IF
+END FUNCTION fib
+
+END PROGRAM
diff --git a/entries/jyoo980/scala/Fib.scala b/entries/jyoo980/scala/Fib.scala
index 05bdd1e..f9107b0 100644
--- a/entries/jyoo980/scala/Fib.scala
+++ b/entries/jyoo980/scala/Fib.scala
@@ -1,4 +1,4 @@
-def fib(n: Int) =
+def fib(n: Int): Int =
   (0 until n).foldLeft((0, 1)) {
     case ((prev, curr), _) => (curr, prev + curr)
   } match {
diff --git a/entries/laelath/fib.bf b/entries/laelath/fib.bf
new file mode 100644
index 0000000..ff7d67a
--- /dev/null
+++ b/entries/laelath/fib.bf
@@ -0,0 +1,3 @@
+>101p011p&:v:-1  <
+   v+g11g10_11g.@
+   >11g01p11p    ^
diff --git a/entries/lizard-business/fib.dats b/entries/lizard-business/fib.dats
new file mode 100644
index 0000000..f6bd5a1
--- /dev/null
+++ b/entries/lizard-business/fib.dats
@@ -0,0 +1,25 @@
+#include "share/atspre_define.hats"
+#include "share/atspre_staload.hats"
+
+dataprop is_fib(int, int) =
+| F0(0, 0) | F1(1, 1)
+| {i, m, n : nat} Fplus(i + 2, m + n) of (is_fib(i, m), is_fib(i + 1, n))
+
+typedef fib(i : int) = [n : nat] (is_fib(i, n) | int(n))
+
+
+fun fib {t : nat} .<>. (t : int(t)) :<> fib(t) =
+let
+  fun go {m, n, i : nat | i <= t} .<t - i>.
+         (M : is_fib(i, m), N : is_fib(i + 1, n) |
+          m : int(m), n : int(n), i : int(i)) :<>
+        fib(t) =
+    if i = t then (M | m)
+    else go(N, Fplus(M, N) | n, m + n, i + 1)
+in
+  go(F0, F1 | 0, 1, 0)
+end
+
+fun fib_(i : Nat) : Nat = let val (_ | res) = fib(i) in res end
+
+implement main0 () = println!("fib(15) = ", fib_(15))
diff --git a/entries/lizard-business/fib.maude b/entries/lizard-business/fib.maude
new file mode 100644
index 0000000..20bc428
--- /dev/null
+++ b/entries/lizard-business/fib.maude
@@ -0,0 +1,27 @@
+smod FIB is
+  pr LIST{Nat} .
+
+  vars M N : Nat .
+  var  Ns  : List{Nat} .
+
+  rl [start]: nil => 0 1 .
+  rl [next]:  Ns M N => Ns M N (M + N) .
+  rl [drop] : Ns N => N .
+
+  strats fib fibgo : Nat @ List{Nat} .
+  sd fib(N)      := start ; fibgo(N) .
+  sd fibgo(0)    := top(drop) .
+  sd fibgo(s(N)) := top(next) ; fibgo(N) .
+endsm
+
+***(
+  Maude> srew nil using fib(10) .
+  srewrite in FIB : nil using fib(10) .
+
+  Solution 1
+  rewrites: 8330 in 12ms cpu (12ms real) (694166 rewrites/second)
+  result NzNat: 89
+
+  No more solutions.
+  rewrites: 8469 in 12ms cpu (13ms real) (705750 rewrites/second)
+)
diff --git a/entries/margoseltzer/efficiency.c b/entries/margoseltzer/efficiency.c
new file mode 100644
index 0000000..6e017f3
--- /dev/null
+++ b/entries/margoseltzer/efficiency.c
@@ -0,0 +1,23 @@
+unsigned long foo(unsigned long n) {
+     if (n < 2) return (n);
+     return(foo(n - 1) + foo(n - 2));
+}
+
+// Efficiency of expression
+
+unsigned long bar(unsigned long n) {
+    unsigned long i, last;
+    unsigned long sum, tmp;
+
+    if (n < 2) return (n);
+    last = 0;
+    sum = 1;
+    for (i = 2; i <= n; i++) {
+        tmp = sum;
+        sum += last;
+        last = tmp;
+    }
+    return (sum);
+}
+
+// Efficiency in resource utilization
diff --git a/entries/meghasinghania22/bash/script.sh b/entries/meghasinghania22/bash/script.sh
new file mode 100644
index 0000000..0cbba4d
--- /dev/null
+++ b/entries/meghasinghania22/bash/script.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+int_regex='^[0-9]+$'
+function fib(){
+    if [ "$1" -le 1 ]; then
+        echo $1
+    else
+        echo $[`fib $[$1 - 1]` + `fib $[$1 - 2]` ]
+    fi
+}
+
+function main(){
+    echo -n "Enter a whole number: "
+    read num
+
+    if [ -z "$num" ]; then
+        echo "Uh oh! Argument required!"
+    elif ! [[ "$num" =~ $int_regex ]]; then
+        echo "Uh oh! Argument must be a number :|"
+    elif [ "$num" -lt 0 ]; then
+        echo "Uh oh! Argument must be a whole number :|"
+    else
+        fib $num
+    fi
+
+}
+
+main
\ No newline at end of file
diff --git a/entries/nritschel/assets/scratch.png b/entries/nritschel/assets/scratch.png
new file mode 100644
index 0000000..5883245
--- /dev/null
+++ b/entries/nritschel/assets/scratch.png
diff --git a/entries/nritschel/fib-java/fib.iml b/entries/nritschel/fib-java/fib.iml
new file mode 100644
index 0000000..815e958
--- /dev/null
+++ b/entries/nritschel/fib-java/fib.iml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library">
+    </orderEntry>
+  </component>
+</module>
\ No newline at end of file
diff --git a/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java b/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java
new file mode 100644
index 0000000..5c404e8
--- /dev/null
+++ b/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java
@@ -0,0 +1,13 @@
+import java.util.HashMap;
+
+public class CachedFibonacciNumberFactory implements FibonacciNumberFactory {
+    private final HashMap<Integer, FibonacciNumber> cachedNumbers = new HashMap<>();
+
+    @Override
+    public FibonacciNumber getFibonacciNumber(int num) {
+        if (!cachedNumbers.containsKey(num)) {
+            cachedNumbers.put(num, new FibonacciNumber(num));
+        }
+        return cachedNumbers.get(num);
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciCalculator.java b/entries/nritschel/fib-java/src/FibonacciCalculator.java
new file mode 100644
index 0000000..8806c20
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciCalculator.java
@@ -0,0 +1,3 @@
+public interface FibonacciCalculator {
+    public int calculateFibonacci(FibonacciNumber fib);
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java b/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java
new file mode 100644
index 0000000..7bb5ee9
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java
@@ -0,0 +1,17 @@
+public class FibonacciCalculatorImpl implements FibonacciCalculator {
+    private final FibonacciNumberFactory factory;
+
+    public FibonacciCalculatorImpl(FibonacciNumberFactory factory) {
+        this.factory = factory;
+    }
+
+    @Override
+    public int calculateFibonacci(FibonacciNumber fib) {
+        if (fib.getNumber() <= 2) {
+            return 1;
+        }
+        else {
+            return factory.getFibonacciNumber(fib.getNumber() - 1).calculate(this) + factory.getFibonacciNumber(fib.getNumber() - 2).calculate(this);
+        }
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciNumber.java b/entries/nritschel/fib-java/src/FibonacciNumber.java
new file mode 100644
index 0000000..fc9381f
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciNumber.java
@@ -0,0 +1,19 @@
+public class FibonacciNumber {
+    private final int number;
+    private Integer result;
+
+    public FibonacciNumber(int number) {
+        this.number = number;
+    }
+
+    public int getNumber() {
+        return number;
+    }
+
+    public int calculate(FibonacciCalculator calculator) {
+        if (result == null) {
+            result = calculator.calculateFibonacci(this);
+        }
+        return result;
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciNumberFactory.java b/entries/nritschel/fib-java/src/FibonacciNumberFactory.java
new file mode 100644
index 0000000..42ef6c2
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciNumberFactory.java
@@ -0,0 +1,3 @@
+public interface FibonacciNumberFactory {
+    public FibonacciNumber getFibonacciNumber(int num);
+}
diff --git a/entries/nritschel/fib-java/src/Main.java b/entries/nritschel/fib-java/src/Main.java
new file mode 100644
index 0000000..8ae46f1
--- /dev/null
+++ b/entries/nritschel/fib-java/src/Main.java
@@ -0,0 +1,21 @@
+public class Main {
+    public static void main(String[] args) {
+        if (args.length < 1) {
+            System.out.println("""
+                    Please provide:
+                    1. fibonacci number to compute, and
+                    2. (optional) the calculation method (naive or cached).""");
+        }
+        else {
+            FibonacciNumberFactory factory;
+            if (args.length >= 2 && args[1].equals("naive")) {
+                factory = new NaiveFibonacciNumberFactory();
+            }
+            else {
+                factory = new CachedFibonacciNumberFactory();
+            }
+            FibonacciCalculator calculator = new FibonacciCalculatorImpl(factory);
+            System.out.println(factory.getFibonacciNumber(Integer.parseInt(args[0])).calculate(calculator));
+        }
+    }
+}
diff --git a/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java b/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java
new file mode 100644
index 0000000..5185a8b
--- /dev/null
+++ b/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java
@@ -0,0 +1,6 @@
+public class NaiveFibonacciNumberFactory implements FibonacciNumberFactory {
+    @Override
+    public FibonacciNumber getFibonacciNumber(int num) {
+        return new FibonacciNumber(num);
+    }
+}
diff --git a/entries/nritschel/scratch/README.md b/entries/nritschel/scratch/README.md
new file mode 100644
index 0000000..e059267
--- /dev/null
+++ b/entries/nritschel/scratch/README.md
@@ -0,0 +1 @@
+<img src="../assets/scratch.png" alt="scratch preview">
\ No newline at end of file
diff --git a/entries/nritschel/scratch/fib.sb3 b/entries/nritschel/scratch/fib.sb3
new file mode 100644
index 0000000..a3cf2cc
--- /dev/null
+++ b/entries/nritschel/scratch/fib.sb3
diff --git a/entries/nritschel/xlsx/fib.xlsx b/entries/nritschel/xlsx/fib.xlsx
new file mode 100644
index 0000000..e1b662d
--- /dev/null
+++ b/entries/nritschel/xlsx/fib.xlsx
diff --git a/entries/nxjfxu/fib.hs b/entries/nxjfxu/fib.hs
new file mode 100644
index 0000000..0f0d871
--- /dev/null
+++ b/entries/nxjfxu/fib.hs
@@ -0,0 +1,5 @@
+fib :: Int -> Int
+fib = (fibs !!)
+  where
+    fibs = 0 : 1 : [fibs !! (i - 2) + fibs !! (i - 1) | i <- [2..]]
+
diff --git a/entries/perryliao/fib.groovy b/entries/perryliao/fib.groovy
new file mode 100644
index 0000000..d625d68
--- /dev/null
+++ b/entries/perryliao/fib.groovy
@@ -0,0 +1,50 @@
+pipeline {
+    agent any
+
+    parameters {
+        string defaultValue: '2', description: 'Number to compute in the Fibonacci Sequence', name: 'num', trim: true
+    }
+
+    stages {
+        stage('Validate Parameter') {
+            steps {
+                script {
+                    assert params.num.isInteger()
+                }
+            }
+        }
+        stage('Create Cache') {
+            steps {
+                script {
+                    if (!fileExists("fibCache")) {
+                        sh 'echo "0\n1" > fibCache'
+                    }
+                }
+            }
+        }
+        stage('Get Fibbonacci') {
+            steps {
+                script {
+                    nComputed = sh(returnStdout: true, script: "wc -l < fibCache").trim().toInteger()
+                    result = fib(params.num.toInteger())
+                    println("The result is F(${params.num}) = ${result}")
+                }
+            }
+        }
+    }
+}
+
+def nComputed
+
+int fib(int n, cache = 'fibCache') {
+    if (n >= nComputed) {
+        // Need to do more recursion
+        result = fib(n - 2, cache) + fib(n - 1, cache)
+        nComputed++
+        sh "echo '${result}' >> ${cache}"
+        return result
+    } else {
+        // Already have what we need, so read from cache
+        return sh(returnStdout: true, script: "sed -n '${n + 1}p' ${cache}").toInteger()
+    }
+}
diff --git a/entries/pkoronkevich/tex/README.md b/entries/pkoronkevich/tex/README.md
new file mode 100644
index 0000000..225773b
--- /dev/null
+++ b/entries/pkoronkevich/tex/README.md
@@ -0,0 +1 @@
+<img src="./render.png" alt="fib.tex preview">
\ No newline at end of file
diff --git a/entries/pkoronkevich/tex/fib.tex b/entries/pkoronkevich/tex/fib.tex
new file mode 100644
index 0000000..cef9138
--- /dev/null
+++ b/entries/pkoronkevich/tex/fib.tex
@@ -0,0 +1,29 @@
+\documentclass[11pt]{article}
+\usepackage[fleqn]{amsmath}
+
+\newcommand{\one}{\lambda f . \lambda x . f \ x}
+\newcommand{\two}{\lambda f . \lambda x . f \ (f \ x)}
+\newcommand{\tru}{\lambda x . \lambda y . x}
+\newcommand{\flse}{\lambda x . \lambda y . y}
+\newcommand{\isz}{\lambda n . n \ (\lambda c . \flse) \ \tru}
+\newcommand{\ife}{\lambda p . \lambda a . \lambda b . p \ a \ b}
+\newcommand{\suc}{\lambda n . \lambda f . \lambda x . f \ (n \ f \ x)}
+\newcommand{\plus}{\lambda m . \lambda n . m \ (\suc) \ n}
+\newcommand{\pred}{\lambda n . \lambda f . \lambda x . n \ (\lambda g . \lambda h . h \ (g \ f)) \ (\lambda u . x) \ (\lambda u . u)}
+\newcommand{\sub}{\lambda m . \lambda n . n \ (\pred) \ m}
+\newcommand{\lleq}{\lambda m . \lambda n . \\ \qquad \isz \ ((\sub) \\ \qquad \ m \ n)}
+\newcommand{\fix}{\lambda g . (\lambda x . g \ (x \ x)) \ (\lambda x . g \ (x \ x))}
+\newcommand{\appo}[2]{#1 \ #2}
+\newcommand{\appt}[3]{#1 \ #2 \ #3}
+
+\begin{document}
+\begin{gather*}
+  \fix \\                                   % recursive function application
+  \quad \lambda r . \lambda n . (\ife) \\   % of fib, which takes itself and n, if expression
+  \quad \ \appt{(\lleq)}{n}{\one} \\        % if n less than or equal to one
+  \quad \ (\one) \\                         % if so, return 1
+  \quad \ (\plus) \\                        % if not, add 
+  \qquad \appo{r}{(\appo{(\pred)}{n})} \\   % the first recursive call, n - 1, to
+  \qquad \appo{r}{(\appt{(\sub)}{n}{\two})} % the second recursive call, n - 2
+\end{gather*}
+\end{document}
diff --git a/entries/pkoronkevich/tex/render.pdf b/entries/pkoronkevich/tex/render.pdf
new file mode 100644
index 0000000..8ee60c7
--- /dev/null
+++ b/entries/pkoronkevich/tex/render.pdf
diff --git a/entries/pkoronkevich/tex/render.png b/entries/pkoronkevich/tex/render.png
new file mode 100644
index 0000000..a1896a2
--- /dev/null
+++ b/entries/pkoronkevich/tex/render.png
diff --git a/entries/rtholmes/Fibonacci series in JavaScript - Stack Overflow.webloc b/entries/rtholmes/Fibonacci series in JavaScript - Stack Overflow.webloc
new file mode 100644
index 0000000..939529d
--- /dev/null
+++ b/entries/rtholmes/Fibonacci series in JavaScript - Stack Overflow.webloc
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>URL</key>
+	<string>https://stackoverflow.com/a/55764043</string>
+</dict>
+</plist>
diff --git a/entries/rxg/fib.rkt b/entries/rxg/fib.rkt
new file mode 100644
index 0000000..61373cd
--- /dev/null
+++ b/entries/rxg/fib.rkt
@@ -0,0 +1,132 @@
+#lang racket
+
+;; fib.rkt - A variety of iterative implementations of the Fibonacci Sequence
+;; All are based on accumulators
+
+;; Natural -> Natural
+;; produce the n'th Fibonacci number
+(define (fib-iter n)
+  (cond
+    [(= n 0) 1]
+    [(= n 1) 1]
+    [else   
+     (let-values ([(n-2 n-1)
+                   ;; i-2 = fib (i-2)
+                   ;; i-1 = fib (i-1)
+                   (for/fold ([i-2 1] [i-1 1])
+                             ([i (in-range 2 n)])
+                     (values i-1 (+ i-2 i-1)))])
+       (+ n-2 n-1))]))
+
+
+(define (fib-iter2 n)
+  (cond
+    [(= n 0) 1]
+    [(= n 1) 1]
+    [else   
+     ;; i-2 = fib (i-2)
+     ;; i-1 = fib (i-1)
+     (let loop ([i-2 1] [i-1 1] [i 2])
+       (if (= i n)
+           (+ i-2 i-1)
+           (loop i-1 (+ i-2 i-1) (add1 i))))]))
+
+(define (fib-iter3 n)
+  (cond
+    [(= n 0) 1]
+    [(= n 1) 1]
+    [else   
+     ;; i-2 = fib (i-2)
+     ;; i-1 = fib (i-1)
+     (do ([i-2 1 i-1]
+          [i-1 1 (+ i-2 i-1)]
+          [i 2 (add1 i)])
+       [(= i n)
+        (+ i-2 i-1)])]))
+
+;; New variant of for with accumulators and a final expression in terms of
+;; the accumulators
+(define-syntax (for/acc stx)
+  (syntax-case stx ()
+    [(_ ([id* init*] ...)
+        (clauses ...)
+        body
+        result)
+     (with-syntax ([original stx])
+     #'(let-values ([(id* ...)
+                   (for/fold/derived original
+                                     ([id* init*] ...)
+                                     (clauses ...)
+                                     body)])
+         result))]))
+
+(define (fib-iter4 n)
+  (cond
+    [(= n 0) 1]
+    [(= n 1) 1]
+    [else   
+     ;; i-2 = fib (i-2)
+     ;; i-1 = fib (i-1)
+     (for/acc ([i-2 1] [i-1 1])
+              ([i (in-range 2 n)])
+              (values i-1 (+ i-2 i-1))
+              (+ i-2 i-1))]))
+
+;; New variant of for with accumulators and a final expression in terms of
+;; the accumulators
+(define-syntax (for/do stx)
+  (syntax-case stx ()
+    [(_ ([id* init* step*] ...)
+        (clauses ...)
+        result)
+     (with-syntax ([original stx])
+     #'(let-values ([(id* ...)
+                   (for/fold/derived original
+                                     ([id* init*] ...)
+                                     (clauses ...)
+                                     (values step* ...))])
+         result))]))
+
+(define (fib-iter5 n)
+  (cond
+    [(= n 0) 1]
+    [(= n 1) 1]
+    [else   
+     ;; i-2 = fib (i-2)
+     ;; i-1 = fib (i-1)
+     (for/do ([i-2 1 i-1] [i-1 1 (+ i-2 i-1)])
+             ([i (in-range 2 n)])
+             (+ i-2 i-1))]))
+
+
+;; Fibonacci's problem, as described by Greg Rawlins in "Compared to What":
+;;   Suppose you have a pair of rabbits and suppose every month each pair
+;;   bears a new pair that from the second month on becomes productive.
+;;   how many pairs of rabbits will you have in a year?
+
+;; Analysis:  
+;; - At time 0 you have 1 unproductive pair: 1 pair, 0 productive pairs
+;; - Each month, each productive pair produces an unproductive pair
+;; - Each month, last months unproductive pairs transition to productive
+;; - how many pairs are there at time step 12?
+
+;; The following function solves the problem *directly* as a
+;; structural recursion over natural numbers with two
+;; accumulators (for lost context (fertile) and result-so-far (total))
+
+;; Natural -> Natural
+;; produce the solution to Fibonacci's problem after n months
+(define (fib-rabbit n0)
+  ;; Accumulator: total is Natural
+  ;; Invariant: total pairs of rabbits after (- n0 n) months
+  ;; Accumulator: fertile is Natural
+  ;; Invariant: productive pairs of rabbits after (- n0 n) months
+  (local [(define (fib-acc fertile total n)
+            (cond [(zero? n) total]
+                  [else 
+                   (fib-acc total      ;; next month, all will be productive
+                            (+         ;; next months pairs include:
+                             total     ;; - this months pairs plus
+                             fertile)  ;; - offspring from productive pairs
+                            (sub1 n))]))] 
+    (fib-acc 0 1 n0)))
diff --git a/entries/shayanh/matrix.go b/entries/shayanh/matrix.go
new file mode 100644
index 0000000..3f374cb
--- /dev/null
+++ b/entries/shayanh/matrix.go
@@ -0,0 +1,40 @@
+package main
+
+type fibmat [2][2]int
+
+func matmul(m1 fibmat, m2 fibmat) (m3 fibmat) {
+	for i := 0; i < 2; i++ {
+		for j := 0; j < 2; j++ {
+			for k := 0; k < 2; k++ {
+				m3[i][j] += m1[i][k] * m2[k][j]
+			}
+		}
+	}
+	return
+}
+
+func matpow(m fibmat, n int) fibmat {
+	if n == 0 {
+		return [2][2]int{
+			{1, 0},
+			{0, 1},
+		}
+	} else if n%2 == 0 {
+		t := matpow(m, n/2)
+		return matmul(t, t)
+	} else {
+		t := matpow(m, n-1)
+		return matmul(t, m)
+	}
+}
+
+func fib(n int) int {
+	m := matpow(
+		[2][2]int{
+			{1, 1},
+			{1, 0},
+		},
+		n,
+	)
+	return m[0][1]
+}
diff --git a/entries/wilbowma/fib-lang b/entries/wilbowma/fib-lang
new file mode 160000
+Subproject 2ec2d1dfd141220882d824cf3dac5b374ed291f
diff --git a/entries/zgrannan/Fib.hs b/entries/zgrannan/Fib.hs
new file mode 100644
index 0000000..1918fc8
--- /dev/null
+++ b/entries/zgrannan/Fib.hs
@@ -0,0 +1,18 @@
+-- Point-less fibonacci
+fib :: Int -> Int
+fib = fix fib'
+  where
+    fib' =
+      ap (when 0 . (0 ==)) .
+      ap (when 1 . (1 ==)) .
+      ap (ap . ((+) .) . (. subtract 1)) (. subtract 2)
+
+    when t c e = if c then t else e
+
+    ap mf m = mf >>= (\f -> m >>= return . f)
+
+    fix f  = f (fix f)
+
+
+main :: IO ()
+main = mapM_ (print . fib) [0 .. 10]