From 80b2c8eb070581c64a0e0c196749f3ef693f23c0 Mon Sep 17 00:00:00 2001
From: Eiden0 <shibashis12@gmail.com>
Date: Wed, 1 Sep 2021 02:12:01 +0530
Subject: [PATCH 1/2] added get Divisors and Fisher Yates Algorithm

---
 src/algorithms/math/divisors.js     | 21 +++++++++++++++++++++
 src/algorithms/math/fisher_Yates.js | 23 +++++++++++++++++++++++
 src/algorithms/math/index.js        |  4 ++++
 test/algorithms/math/divisors.js    | 25 +++++++++++++++++++++++++
 test/algorithms/math/fisherYates.js | 15 +++++++++++++++
 5 files changed, 88 insertions(+)
 create mode 100644 src/algorithms/math/divisors.js
 create mode 100644 src/algorithms/math/fisher_Yates.js
 create mode 100644 test/algorithms/math/divisors.js
 create mode 100644 test/algorithms/math/fisherYates.js

diff --git a/src/algorithms/math/divisors.js b/src/algorithms/math/divisors.js
new file mode 100644
index 00000000..98bb6d5e
--- /dev/null
+++ b/src/algorithms/math/divisors.js
@@ -0,0 +1,21 @@
+/**
+ * Calculates the list of divisors of a number in sorted order
+ * @param  {Number} n number
+ * @return {Array}   Array of Divisors
+ * Time Complexity = O(n ^ 0.5)
+ */
+ const getDivisors = (n) => {
+  let divisors = [];
+  if (n < 1) return [];
+  const tempArray = [];
+  for (let i = 1; i * i <= n; i += 1) {
+    if (n % i === 0) {
+      divisors.push(i);
+      if (i !== n / i) tempArray.push(n / i);
+    }
+  }
+  divisors = divisors.concat(tempArray.reverse());
+  return divisors;
+};
+
+module.exports = getDivisors;
diff --git a/src/algorithms/math/fisher_Yates.js b/src/algorithms/math/fisher_Yates.js
new file mode 100644
index 00000000..644130a5
--- /dev/null
+++ b/src/algorithms/math/fisher_Yates.js
@@ -0,0 +1,23 @@
+/**
+ * Shuffle array in-place using Fisher-Yates Algorithm
+ * @param  {Array} array Array to be shuffled
+ * @return {Array}   Shuffled Array
+ *
+ */
+ const Shuffle = (array) => {
+  let currentIndex = array.length;
+  let randomIndex;
+
+  while (currentIndex != 0) {
+
+    randomIndex = Math.floor(Math.random() * currentIndex);
+    currentIndex -= 1;
+
+    [array[currentIndex], array[randomIndex]] = [
+      array[randomIndex], array[currentIndex]];
+  }
+
+  return array;
+};
+
+module.exports = Shuffle;
\ No newline at end of file
diff --git a/src/algorithms/math/index.js b/src/algorithms/math/index.js
index 41b2e488..47995009 100644
--- a/src/algorithms/math/index.js
+++ b/src/algorithms/math/index.js
@@ -3,8 +3,12 @@ const gcd = require('./gcd');
 const fastexp = require('./fast_exp');
 const lcm = require('./lcm');
 const modularInverse = require('./modular_inverse');
+const Shuffle = require('./fisher_Yates');
+const getDivisors = require('./divisors');
 
 module.exports = {
+  Shuffle,
+  getDivisors,
   extendedEuclidean,
   gcd,
   fastexp,
diff --git a/test/algorithms/math/divisors.js b/test/algorithms/math/divisors.js
new file mode 100644
index 00000000..9710e197
--- /dev/null
+++ b/test/algorithms/math/divisors.js
@@ -0,0 +1,25 @@
+/* eslint-env mocha */
+const getDivisors = require('../../../src').algorithms.math.getDivisors;
+
+const assert = require('assert');
+
+describe('Divisors', () => {
+  it('should return empty array for number 0', () => {
+    assert.deepEqual(getDivisors(0), []);
+  });
+
+  it('should return [] for negative numbers ', () => {
+    assert.deepEqual(getDivisors(-3), []);
+  });
+
+  it('should return [1] for 1', () => {
+    assert.deepEqual(getDivisors(1), [1]);
+
+  });
+
+  it('should return divisors of a number', () => {
+    assert.deepEqual(getDivisors(100), [1, 2, 4, 5, 10, 20, 25, 50, 100]);
+    assert.deepEqual(getDivisors(10), [1, 2, 5, 10]);
+    assert.deepEqual(getDivisors(125), [1, 5, 25, 125]);
+  });
+});
\ No newline at end of file
diff --git a/test/algorithms/math/fisherYates.js b/test/algorithms/math/fisherYates.js
new file mode 100644
index 00000000..2d7adf68
--- /dev/null
+++ b/test/algorithms/math/fisherYates.js
@@ -0,0 +1,15 @@
+/* eslint-env mocha */
+const Shuffle = require('../../../src').algorithms.math.Shuffle;
+
+const assert = require('assert');
+
+describe('Shuffle', () => {
+  it('should return empty array for an empty array', () => {
+    assert.deepEqual(Shuffle([]), []);
+  });
+
+  it('length of both the array should be same ', () => {
+    const arr = [1, 2, 3];
+    assert.deepEqual(Shuffle(arr).length, 3);
+  });
+});
\ No newline at end of file

From f188db68d2955a88f4a522dfd8512fc0b18b91be Mon Sep 17 00:00:00 2001
From: Eiden0 <shibashis12@gmail.com>
Date: Wed, 1 Sep 2021 02:26:06 +0530
Subject: [PATCH 2/2] prettied code

---
 src/algorithms/math/divisors.js     | 2 +-
 src/algorithms/math/fisher_Yates.js | 7 +++----
 test/algorithms/math/divisors.js    | 3 +--
 test/algorithms/math/fisherYates.js | 2 +-
 4 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/algorithms/math/divisors.js b/src/algorithms/math/divisors.js
index 98bb6d5e..e41d23bc 100644
--- a/src/algorithms/math/divisors.js
+++ b/src/algorithms/math/divisors.js
@@ -4,7 +4,7 @@
  * @return {Array}   Array of Divisors
  * Time Complexity = O(n ^ 0.5)
  */
- const getDivisors = (n) => {
+const getDivisors = (n) => {
   let divisors = [];
   if (n < 1) return [];
   const tempArray = [];
diff --git a/src/algorithms/math/fisher_Yates.js b/src/algorithms/math/fisher_Yates.js
index 644130a5..d7239d4f 100644
--- a/src/algorithms/math/fisher_Yates.js
+++ b/src/algorithms/math/fisher_Yates.js
@@ -4,12 +4,11 @@
  * @return {Array}   Shuffled Array
  *
  */
- const Shuffle = (array) => {
+const Shuffle = (array) => {
   let currentIndex = array.length;
   let randomIndex;
 
-  while (currentIndex != 0) {
-
+  while (currentIndex !== 0) {
     randomIndex = Math.floor(Math.random() * currentIndex);
     currentIndex -= 1;
 
@@ -20,4 +19,4 @@
   return array;
 };
 
-module.exports = Shuffle;
\ No newline at end of file
+module.exports = Shuffle;
diff --git a/test/algorithms/math/divisors.js b/test/algorithms/math/divisors.js
index 9710e197..f008c0db 100644
--- a/test/algorithms/math/divisors.js
+++ b/test/algorithms/math/divisors.js
@@ -14,7 +14,6 @@ describe('Divisors', () => {
 
   it('should return [1] for 1', () => {
     assert.deepEqual(getDivisors(1), [1]);
-
   });
 
   it('should return divisors of a number', () => {
@@ -22,4 +21,4 @@ describe('Divisors', () => {
     assert.deepEqual(getDivisors(10), [1, 2, 5, 10]);
     assert.deepEqual(getDivisors(125), [1, 5, 25, 125]);
   });
-});
\ No newline at end of file
+});
diff --git a/test/algorithms/math/fisherYates.js b/test/algorithms/math/fisherYates.js
index 2d7adf68..3fb938f6 100644
--- a/test/algorithms/math/fisherYates.js
+++ b/test/algorithms/math/fisherYates.js
@@ -12,4 +12,4 @@ describe('Shuffle', () => {
     const arr = [1, 2, 3];
     assert.deepEqual(Shuffle(arr).length, 3);
   });
-});
\ No newline at end of file
+});