fibonacci optimize with Memory pattern

Author: rajratnamaitry

src/others/fibonacciMemory.js

@@ -0,0 +1,32 @@
+/**
+ * Nth number of fibonacciMemory's sequence
+ *
+ * Returns the nth number of fibonacciMemory's sequence.
+ *
+ * @public
+ *
+ * @example
+ * var fibonacciMemory = require('path-to-algorithms/src/others/fibonacciMemory').fibonacciMemory;
+ * var nth = fibonacciMemory(20);
+ *
+ * console.log(nth); // 6765
+ *
+ * @param {Number} n The nth position in fibonacciMemory's sequence
+ *
+ * @module others/fibonacciMemory
+*/
+(function (exports) {
+    'use strict';
+
+    function fibonacciMemory(n) {
+        var i = 0;
+        var aux = [0, 1];
+        while (n != i) {
+            aux[i + 2] = aux[i] + aux[i + 1];
+            i++;
+        }
+        return aux[i];
+    }
+
+    exports.fibonacciMemory = fibonacciMemory;
+})(typeof window === 'undefined' ? module.exports : window);

test/others/fibonacciMemory.spec.js

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+var mod = require('../../src/others/fibonacciMemory.js');
+var fibonacci = mod.fibonacciMemory;
+
+describe('fibonacci with Memory algorithm', function () {
+  'use strict';
+
+  it('should return value 1 with input 1.', function () {
+    expect(fibonacci(1)).toBe(1);
+  });
+  it('should return value 6 with input 8.', function () {
+    expect(fibonacci(6)).toBe(8);
+  });
+  it('should return value 7 with input 13.', function () {
+    expect(fibonacci(7)).toBe(13);
+  });
+  it('should return value 8 with input 21.', function () {
+    expect(fibonacci(8)).toBe(21);
+  });
+  it('should return value 9 with input 34.', function () {
+    expect(fibonacci(9)).toBe(34);
+  });
+  it('should return value 10 with input 55.', function () {
+    expect(fibonacci(10)).toBe(55);
+  });  
+  it('should be 135301852344706760000 with input 98.', function () {
+    expect(fibonacci(98)).toBe(135301852344706760000);
+  });
+});