From 41ddee7074a44a0fada60b39c838cad334968d2f Mon Sep 17 00:00:00 2001
From: devcer <viswanathamsantosh@gmail.com>
Date: Thu, 14 Oct 2021 21:10:34 +0530
Subject: [PATCH 1/3] Added Maximum product of 3 numbers in an array

---
 Dynamic-Programming/MaxProductOfThree.js      | 37 +++++++++++++++++++
 .../tests/MaxProductOfThree.test.js           | 15 ++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 Dynamic-Programming/MaxProductOfThree.js
 create mode 100644 Dynamic-Programming/tests/MaxProductOfThree.test.js

diff --git a/Dynamic-Programming/MaxProductOfThree.js b/Dynamic-Programming/MaxProductOfThree.js
new file mode 100644
index 000000000..24a2ad6e9
--- /dev/null
+++ b/Dynamic-Programming/MaxProductOfThree.js
@@ -0,0 +1,37 @@
+/**
+ *  Given an array of numbers, return the maximum product
+ *  of 3 numbers from the array
+ * @param {number[]} arrayItems
+ * @returns number
+ */
+export function maxProductOfThree(arrayItems) {
+  // if size is less than 3, no triplet exists
+  let n = arrayItems.length
+  if (n < 3) return -1
+  let max1 = arrayItems[0],
+    max2 = -1,
+    max3 = -1,
+    min1 = arrayItems[0],
+    min2 = -1
+  for (let i = 1; i < n; i++) {
+    if (arrayItems[i] > max1) {
+      max3 = max2
+      max2 = max1
+      max1 = arrayItems[i]
+    } else if (max2 === -1 || arrayItems[i] > max2) {
+      max3 = max2
+      max2 = arrayItems[i]
+    } else if (max3 === -1 || arrayItems[i] > max3) {
+      max3 = arrayItems[i]
+    }
+    if (arrayItems[i] < min1) {
+      min2 = min1
+      min1 = arrayItems[i]
+    } else if (min2 === -1 || arrayItems[i] < min2) {
+      min2 = arrayItems[i]
+    }
+  }
+  let prod1 = max1 * max2 * max3,
+    prod2 = max1 * min1 * min2
+  return Math.max(prod1, prod2)
+}
diff --git a/Dynamic-Programming/tests/MaxProductOfThree.test.js b/Dynamic-Programming/tests/MaxProductOfThree.test.js
new file mode 100644
index 000000000..41861bac1
--- /dev/null
+++ b/Dynamic-Programming/tests/MaxProductOfThree.test.js
@@ -0,0 +1,15 @@
+import { maxProductOfThree } from '../MaxProductOfThree'
+
+describe('MaxProductOfThree', () => {
+  it('expects to return -1 for array with only 2 numbers', () => {
+    expect(maxProductOfThree([1, 3])).toBe(-1)
+  })
+
+  it('expects to return 300 as the maximum product', () => {
+    expect(maxProductOfThree([10, 6, 5, 3, 1, -10])).toBe(300)
+  })
+
+  it('expects to return 300 as the maximum product', () => {
+    expect(maxProductOfThree([10, -6, 5, 3, 1, -10])).toBe(600)
+  })
+})

From b3377bb79cb7275951f42aab0d950dbff9e14f1f Mon Sep 17 00:00:00 2001
From: devcer <viswanathamsantosh@gmail.com>
Date: Thu, 14 Oct 2021 21:14:48 +0530
Subject: [PATCH 2/3] added a link to explanation

---
 Dynamic-Programming/MaxProductOfThree.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Dynamic-Programming/MaxProductOfThree.js b/Dynamic-Programming/MaxProductOfThree.js
index 24a2ad6e9..811913c69 100644
--- a/Dynamic-Programming/MaxProductOfThree.js
+++ b/Dynamic-Programming/MaxProductOfThree.js
@@ -1,6 +1,7 @@
 /**
  *  Given an array of numbers, return the maximum product
  *  of 3 numbers from the array
+ *  https://wsvincent.com/javascript-three-sum-highest-product-of-three-numbers/
  * @param {number[]} arrayItems
  * @returns number
  */

From 67ec915d97a85ca17bb6c063e7b88ee1ce92206e Mon Sep 17 00:00:00 2001
From: devcer <viswanathamsantosh@gmail.com>
Date: Fri, 15 Oct 2021 21:49:29 +0530
Subject: [PATCH 3/3] added throwing an error when array with <3 items is
 passed

---
 Dynamic-Programming/MaxProductOfThree.js            | 2 +-
 Dynamic-Programming/tests/MaxProductOfThree.test.js | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Dynamic-Programming/MaxProductOfThree.js b/Dynamic-Programming/MaxProductOfThree.js
index 811913c69..1e7ebe3e1 100644
--- a/Dynamic-Programming/MaxProductOfThree.js
+++ b/Dynamic-Programming/MaxProductOfThree.js
@@ -8,7 +8,7 @@
 export function maxProductOfThree(arrayItems) {
   // if size is less than 3, no triplet exists
   let n = arrayItems.length
-  if (n < 3) return -1
+  if (n < 3) throw new Error('Triplet cannot exist with the given array')
   let max1 = arrayItems[0],
     max2 = -1,
     max3 = -1,
diff --git a/Dynamic-Programming/tests/MaxProductOfThree.test.js b/Dynamic-Programming/tests/MaxProductOfThree.test.js
index 41861bac1..32aaec542 100644
--- a/Dynamic-Programming/tests/MaxProductOfThree.test.js
+++ b/Dynamic-Programming/tests/MaxProductOfThree.test.js
@@ -1,8 +1,10 @@
 import { maxProductOfThree } from '../MaxProductOfThree'
 
 describe('MaxProductOfThree', () => {
-  it('expects to return -1 for array with only 2 numbers', () => {
-    expect(maxProductOfThree([1, 3])).toBe(-1)
+  it('expects to throw error for array with only 2 numbers', () => {
+    expect(() => {
+      maxProductOfThree([1, 3])
+    }).toThrow('Triplet cannot exist with the given array')
   })
 
   it('expects to return 300 as the maximum product', () => {