Create FibonacciNumber.js (#378)

* Create FibonacciNumber.js

* Update FibonacciNumber.js

Co-authored-by: vinayak <itssvinayak@gmail.com>

Dynamic-Programming/FibonacciNumber.js

@@ -0,0 +1,18 @@
+//  https://en.wikipedia.org/wiki/Fibonacci_number
+
+const fibonacci = (N) => {
+  // creating array to store values
+  const memo = new Array(N + 1)
+  memo[0] = 0
+  memo[1] = 1
+  for (let i = 2; i <= N; i++) {
+    memo[i] = memo[i - 1] + memo[i - 2]
+  }
+  return memo[N]
+}
+
+// testing
+(() => {
+  const number = 5
+  console.log(number + 'th Fibonacci number is ' + fibonacci(number))
+})()