merge

Author: SumeetHaryani

README.md

@@ -62,3 +62,23 @@ Collection of interview questions with Unit Tests. Problems includes Data Struct
 
 - [Caeser Cipher](src/_Classics_/caeser_cipher)
 - [Fibonacci](src/_Classics_/fibonacci)
+
+---
+
+## CONTRIBUTION Guide
+
+It's great to know that you want to contribute to this repo. Thanks for taking interest. Before you start, read the following carefully. 
+
+- When adding a new **problem** with solution
+  - Take care of the filename convention (Very Important)
+  - Problem statement should be there with examples
+  - Make sure you add the Run Time complexity of your solution
+  - Please take care of the segregation of the Problems as per the given Folder Structure
+  - It's great if you can add the **Unit Tests** to verify your solutions as well
+  - Strictly follow ESLINT rules
+
+- When adding a Unit Test
+  - Take care of the file name convention
+  - Make sure CI (Travis) is passing
+  
+Keep an eye on this guide, it's subjected to change frequently. 

src/_Problems_/max-product-of-3-numbers/index.js

@@ -63,3 +63,5 @@ function maxProductof3NumbersII(arr) {
 
   return p1 > p2 ? p1 : p2;
 }
+
+module.exports = { maxProductof3Numbers, maxProductof3NumbersII };

src/_Problems_/max-product-of-3-numbers/max-product-of-3-numbers.test.js

@@ -0,0 +1,39 @@
+const { maxProductof3Numbers, maxProductof3NumbersII } = require(".");
+
+describe("Maximum Product of three numbers", () => {
+  it("throws an error with no Array is passed", () => {
+    expect(() => {
+      maxProductof3Numbers("xunda");
+    }).toThrowError();
+    expect(() => {
+      maxProductof3NumbersII("xunda");
+    }).toThrowError();
+  });
+
+  it("returns the product of an array with 3 numbers", () => {
+    expect(maxProductof3Numbers([1, 2, 3])).toEqual(6);
+    expect(maxProductof3NumbersII([1, 2, 3])).toEqual(6);
+  });
+
+  it("returns the product of an array with positive and negative numbers", () => {
+    expect(maxProductof3Numbers([-10, -10, 2, 3])).toEqual(300);
+    expect(maxProductof3NumbersII([-10, -10, 2, 3])).toEqual(300);
+  });
+
+  it("returns the product of an array with negative numbers", () => {
+    expect(maxProductof3Numbers([-10, -1, -2, -10])).toEqual(-20);
+    expect(maxProductof3NumbersII([-10, -1, -2, -10])).toEqual(-20);
+  });
+
+  it("returns the proper calculation if the array is large", () => {
+    const largeArray = [100, 100, 100, 12, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 12, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 12, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 45, 4, 3, 7, 8, 1, 3, 7, 8, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 12, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 1, 12, 3, 45, 4, 3, 7, 8, 1, 3, 7, 8, 1, 4, 3, 7, 8, 1, 3, 7, 8, 45, 4, 3, 7, 8, 1, 3, 7, 8];
+    expect(maxProductof3Numbers(largeArray)).toEqual(100 * 100 * 100);
+    expect(maxProductof3NumbersII(largeArray)).toEqual(100 * 100 * 100);
+  });
+
+  it("returns an error if there are less than 3 numbers", () => {
+    expect(() => {
+      maxProductof3Numbers([-10, -1]);
+    }).toThrowError();
+  });
+});