From d671327ebe63832434285ef96cabf255e11bf2cd Mon Sep 17 00:00:00 2001
From: Nikunj Bisht <52692588+Nikunj-bisht@users.noreply.github.com>
Date: Thu, 26 Oct 2023 19:08:19 +0530
Subject: [PATCH] feat: added find subsets algorithm using bitmanipulation
 (#1514)

* feat: added find subsets algorithm using bitmanipulation

* file name fix

* test file name fix

* fix: codespell fix

* error handled

* added test cases for error
---
 Bit-Manipulation/GenerateSubSets.js           | 34 ++++++++++++++++++
 Bit-Manipulation/test/GenerateSubSets.test.js | 36 +++++++++++++++++++
 2 files changed, 70 insertions(+)
 create mode 100644 Bit-Manipulation/GenerateSubSets.js
 create mode 100644 Bit-Manipulation/test/GenerateSubSets.test.js

diff --git a/Bit-Manipulation/GenerateSubSets.js b/Bit-Manipulation/GenerateSubSets.js
new file mode 100644
index 000000000..9ee131d75
--- /dev/null
+++ b/Bit-Manipulation/GenerateSubSets.js
@@ -0,0 +1,34 @@
+/**
+ * @function generateSubSets
+ * @param {Array} inputArray
+ * @returns {Array}
+ * @example [1,2] -> [[],[1],[2],[1,2]]
+ */
+
+// The time complexity of this algorithm is BigO(2^n) where n is the length of array
+function generateSubSets(inputArray) {
+  if (!Array.isArray(inputArray)) {
+    throw new Error('Provided input is not an array')
+  }
+  if (inputArray.length > 32) {
+    throw new RangeError('Error size should be less than equal to 32')
+  }
+  let arrayLength = inputArray.length
+  let subSets = []
+  // loop till (2^n) - 1
+  for (let i = 0; i < 1 << arrayLength; i++) {
+    let subSet = []
+    for (let j = 0; j < arrayLength; j++) {
+      // 1 << j it shifts binary digit 1 by j positions and then we perform
+      // and by AND operation we are checking whetheer jth bit
+      // in i is set to 1 if result is non zero just add into set
+      if (i & (1 << j)) {
+        subSet.push(inputArray[j])
+      }
+    }
+    subSets.push(subSet)
+  }
+  return subSets
+}
+
+export { generateSubSets }
diff --git a/Bit-Manipulation/test/GenerateSubSets.test.js b/Bit-Manipulation/test/GenerateSubSets.test.js
new file mode 100644
index 000000000..2e3b90ba7
--- /dev/null
+++ b/Bit-Manipulation/test/GenerateSubSets.test.js
@@ -0,0 +1,36 @@
+import { generateSubSets } from '../GenerateSubSets'
+
+describe('subSets', () => {
+  it('find the subsets', () => {
+    expect(generateSubSets([1, 2, 3])).toEqual([
+      [],
+      [1],
+      [2],
+      [1, 2],
+      [3],
+      [1, 3],
+      [2, 3],
+      [1, 2, 3]
+    ])
+    expect(generateSubSets([1, 2])).toEqual([[], [1], [2], [1, 2]])
+    expect(generateSubSets([1, 2, 3])).toEqual([
+      [],
+      [1],
+      [2],
+      [1, 2],
+      [3],
+      [1, 3],
+      [2, 3],
+      [1, 2, 3]
+    ])
+    expect(() => generateSubSets('invalid')).toThrow(
+      'Provided input is not an array'
+    )
+    expect(() =>
+      generateSubSets([
+        1, 2, 2, 1, 2, 3, 4, 3, 2, 3, 4, 3, 2, 2, 2, 3, 12, 11, 4, 2, 2, 2, 2,
+        1, 2, 3, 5, 6, 7, 7, 8, 6, 5, 6, 7, 8, 9, 8, 0, 6
+      ])
+    ).toThrow('Error size should be less than equal to 32')
+  })
+})