From 8661dd37db614e7ae76cb252d8795f04136eb90d Mon Sep 17 00:00:00 2001
From: Mayank <mrunknown3212@gmail.com>
Date: Sat, 4 Oct 2025 12:42:49 +0530
Subject: [PATCH 1/2] Added minimum window substring implementation and test
 file

---
 Sliding-Windows/MinimumWindowSubstring.js     | 42 +++++++++++++++++++
 .../test/MinimumWindowSubstring.test.js       | 17 ++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 Sliding-Windows/MinimumWindowSubstring.js
 create mode 100644 Sliding-Windows/test/MinimumWindowSubstring.test.js

diff --git a/Sliding-Windows/MinimumWindowSubstring.js b/Sliding-Windows/MinimumWindowSubstring.js
new file mode 100644
index 0000000000..8977c093c6
--- /dev/null
+++ b/Sliding-Windows/MinimumWindowSubstring.js
@@ -0,0 +1,42 @@
+/*
+ * Author: Mayank
+ * Minimum Window Substring implementation in JavaScript
+ * Finds the smallest substring of s that contains all characters of t.
+ */
+
+function minWindowSubstring(s, t) {
+  if (t.length > s.length) return ""
+
+  const need = {}
+  for (let char of t) {
+    need[char] = (need[char] || 0) + 1
+  }
+
+  let left = 0
+  let count = t.length
+  let minLen = Infinity
+  let minStart = 0
+
+  for (let right = 0; right < s.length; right++) {
+    if (need[s[right]] !== undefined) {
+      if (need[s[right]] > 0) count--
+      need[s[right]]--
+    }
+
+    while (count === 0) {
+      if (right - left + 1 < minLen) {
+        minLen = right - left + 1
+        minStart = left
+      }
+      if (need[s[left]] !== undefined) {
+        need[s[left]]++
+        if (need[s[left]] > 0) count++
+      }
+      left++
+    }
+  }
+
+  return minLen === Infinity ? "" : s.substring(minStart, minStart + minLen)
+}
+
+export { minWindowSubstring }
diff --git a/Sliding-Windows/test/MinimumWindowSubstring.test.js b/Sliding-Windows/test/MinimumWindowSubstring.test.js
new file mode 100644
index 0000000000..7fd48683a8
--- /dev/null
+++ b/Sliding-Windows/test/MinimumWindowSubstring.test.js
@@ -0,0 +1,17 @@
+/*
+ * Test file for Minimum Window Substring
+ */
+
+import { minWindowSubstring } from "../MinimumWindowSubstring.js"
+
+test("return smallest window containing all characters", () => {
+  expect(minWindowSubstring("ADOBECODEBANC", "ABC")).toBe("BANC")
+})
+
+test("return empty string if no window found", () => {
+  expect(minWindowSubstring("HELLO", "XYZ")).toBe("")
+})
+
+test("return full string if it matches exactly", () => {
+  expect(minWindowSubstring("ABC", "ABC")).toBe("ABC")
+})

From 64137f5e725484941fb9669cd8db790a2ecd00a3 Mon Sep 17 00:00:00 2001
From: Mayank <mrunknown3212@gmail.com>
Date: Sat, 4 Oct 2025 13:14:02 +0530
Subject: [PATCH 2/2] Added minimum window substring implementation and test
 file with prettier code

---
 Maths/MobiusFunction.js                            |  4 ++--
 Sliding-Windows/MinimumWindowSubstring.js          |  4 ++--
 .../test/MinimumWindowSubstring.test.js            | 14 +++++++-------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Maths/MobiusFunction.js b/Maths/MobiusFunction.js
index bd268b8bbd..4239d6ab31 100644
--- a/Maths/MobiusFunction.js
+++ b/Maths/MobiusFunction.js
@@ -28,6 +28,6 @@ export const mobiusFunction = (number) => {
   return primeFactorsArray.length !== new Set(primeFactorsArray).size
     ? 0
     : primeFactorsArray.length % 2 === 0
-    ? 1
-    : -1
+      ? 1
+      : -1
 }
diff --git a/Sliding-Windows/MinimumWindowSubstring.js b/Sliding-Windows/MinimumWindowSubstring.js
index 8977c093c6..1616c3a6b7 100644
--- a/Sliding-Windows/MinimumWindowSubstring.js
+++ b/Sliding-Windows/MinimumWindowSubstring.js
@@ -5,7 +5,7 @@
  */
 
 function minWindowSubstring(s, t) {
-  if (t.length > s.length) return ""
+  if (t.length > s.length) return ''
 
   const need = {}
   for (let char of t) {
@@ -36,7 +36,7 @@ function minWindowSubstring(s, t) {
     }
   }
 
-  return minLen === Infinity ? "" : s.substring(minStart, minStart + minLen)
+  return minLen === Infinity ? '' : s.substring(minStart, minStart + minLen)
 }
 
 export { minWindowSubstring }
diff --git a/Sliding-Windows/test/MinimumWindowSubstring.test.js b/Sliding-Windows/test/MinimumWindowSubstring.test.js
index 7fd48683a8..c32371ef6e 100644
--- a/Sliding-Windows/test/MinimumWindowSubstring.test.js
+++ b/Sliding-Windows/test/MinimumWindowSubstring.test.js
@@ -2,16 +2,16 @@
  * Test file for Minimum Window Substring
  */
 
-import { minWindowSubstring } from "../MinimumWindowSubstring.js"
+import { minWindowSubstring } from '../MinimumWindowSubstring.js'
 
-test("return smallest window containing all characters", () => {
-  expect(minWindowSubstring("ADOBECODEBANC", "ABC")).toBe("BANC")
+test('return smallest window containing all characters', () => {
+  expect(minWindowSubstring('ADOBECODEBANC', 'ABC')).toBe('BANC')
 })
 
-test("return empty string if no window found", () => {
-  expect(minWindowSubstring("HELLO", "XYZ")).toBe("")
+test('return empty string if no window found', () => {
+  expect(minWindowSubstring('HELLO', 'XYZ')).toBe('')
 })
 
-test("return full string if it matches exactly", () => {
-  expect(minWindowSubstring("ABC", "ABC")).toBe("ABC")
+test('return full string if it matches exactly', () => {
+  expect(minWindowSubstring('ABC', 'ABC')).toBe('ABC')
 })