From e100fe81c39cb47348046319e99ec2f2894dab93 Mon Sep 17 00:00:00 2001
From: helloShen <symantec__@hotmail.com>
Date: Tue, 8 Feb 2022 14:19:06 -0500
Subject: [PATCH] Add recursive and dynamic programming solution to fibonacci

---
 fibonacci/fibonacci.js | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/fibonacci/fibonacci.js b/fibonacci/fibonacci.js
index 29ea89d..8d0e059 100644
--- a/fibonacci/fibonacci.js
+++ b/fibonacci/fibonacci.js
@@ -1,6 +1,6 @@
 const fibonacci = function(count) {
   if (count < 0) return "OOPS";
-  if (count === 0) return 0;
+  if (count == 0) return 0;
   let a = 0;
   let b = 1;
   for (let i = 1; i < count; i++) {
@@ -11,4 +11,25 @@ const fibonacci = function(count) {
   return b;
 };
 
-module.exports = fibonacci;
+/* naive recursive */
+const fibonacciRecursive = function(count) {
+  if (count < 0) return 'OOPS';
+  if (count == 0) return 0;
+  if (count == 1) return 1;
+  return fibonacciRecursive(count - 1) + fibonacciRecursive(count - 2);
+}
+
+/* Dynamic Programming (DP) recursive */
+const fibonacciDp= function(count) {
+  return fibonacciDpHelper(count, {'0': 0, '1': 1});
+}
+
+const fibonacciDpHelper = function(count, memo) {
+  if (count < 0) return 'OOPS';
+  if (memo.hasOwnProperty(`${count}`)) return memo[`${count}`];
+  const result = fibonacciDpHelper(count - 1, memo) + fibonacciDpHelper(count - 2, memo);
+  memo[`${count}`] = result;
+  return result;
+}
+
+module.exports = fibonacci;
\ No newline at end of file