From 2e2361e496eae35582208596ec293c4f747a836c Mon Sep 17 00:00:00 2001
From: k7 <kesavanvel77@gmail.com>
Date: Tue, 5 Nov 2024 22:27:57 +0530
Subject: [PATCH 1/2] feat: implement sliding window algorithms for fixed and
dynamic sizes with tests
---
.../LongestSubarrayWithSumAtMost.js | 21 +++++++++++++++
Sliding-Windows/MaxSumSubarrayFixed.js | 26 +++++++++++++++++++
.../test/LongestSubarrayWithSumAtMost.test.js | 24 +++++++++++++++++
.../test/MaxSumSubarrayFixed.test.js | 22 ++++++++++++++++
4 files changed, 93 insertions(+)
create mode 100644 Sliding-Windows/LongestSubarrayWithSumAtMost.js
create mode 100644 Sliding-Windows/MaxSumSubarrayFixed.js
create mode 100644 Sliding-Windows/test/LongestSubarrayWithSumAtMost.test.js
create mode 100644 Sliding-Windows/test/MaxSumSubarrayFixed.test.js
diff --git a/Sliding-Windows/LongestSubarrayWithSumAtMost.js b/Sliding-Windows/LongestSubarrayWithSumAtMost.js
new file mode 100644
index 0000000000..b970539ee0
--- /dev/null
+++ b/Sliding-Windows/LongestSubarrayWithSumAtMost.js
@@ -0,0 +1,21 @@
+/**
+ * Function to find the longest subarray with a sum <= target.
+ *
+ * @param {number[]} arr - The input array of numbers.
+ * @param {number} target - The target sum for the dynamic window.
+ * @returns {number} - The length of the longest subarray with a sum <= target.
+ */
+export function longestSubarrayWithSumAtMost(arr, target) {
+ let maxLength = 0
+ let windowSum = 0
+ let left = 0
+ for (let right = 0; right < arr.length; right++) {
+ windowSum += arr[right]
+ while (windowSum > target) {
+ windowSum -= arr[left]
+ left++
+ }
+ maxLength = Math.max(maxLength, right - left + 1)
+ }
+ return maxLength
+}
diff --git a/Sliding-Windows/MaxSumSubarrayFixed.js b/Sliding-Windows/MaxSumSubarrayFixed.js
new file mode 100644
index 0000000000..ba8b844f14
--- /dev/null
+++ b/Sliding-Windows/MaxSumSubarrayFixed.js
@@ -0,0 +1,26 @@
+/**
+ * Function to find the maximum sum of a subarray of fixed size k.
+ *
+ * @param {number[]} arr - The input array of numbers.
+ * @param {number} k - The fixed size of the subarray.
+ * @returns {number} - The maximum sum of any subarray of size k.
+ * @throws {RangeError} - If k is larger than the array length or less than 1.
+ */
+export function maxSumSubarrayFixed(arr, k) {
+ if (k > arr.length || k < 1) {
+ throw new RangeError(
+ 'Subarray size k must be between 1 and the length of the array'
+ )
+ }
+ let maxSum = 0
+ let windowSum = 0
+ for (let i = 0; i < k; i++) {
+ windowSum += arr[i]
+ }
+ maxSum = windowSum
+ for (let i = k; i < arr.length; i++) {
+ windowSum += arr[i] - arr[i - k]
+ maxSum = Math.max(maxSum, windowSum)
+ }
+ return maxSum
+}
diff --git a/Sliding-Windows/test/LongestSubarrayWithSumAtMost.test.js b/Sliding-Windows/test/LongestSubarrayWithSumAtMost.test.js
new file mode 100644
index 0000000000..c33188fffb
--- /dev/null
+++ b/Sliding-Windows/test/LongestSubarrayWithSumAtMost.test.js
@@ -0,0 +1,24 @@
+import { longestSubarrayWithSumAtMost } from '../LongestSubarrayWithSumAtMost'
+
+describe('Dynamic-size Sliding Window - longestSubarrayWithSumAtMost', () => {
+ it('should return the longest subarray length with sum <= target', () => {
+ const arr = [1, 2, 3, 4, 5]
+ const target = 7
+ const result = longestSubarrayWithSumAtMost(arr, target)
+ expect(result).toBe(3)
+ })
+
+ it('should return the full array length if the entire sum is within the target', () => {
+ const arr = [1, 1, 1, 1]
+ const target = 4
+ const result = longestSubarrayWithSumAtMost(arr, target)
+ expect(result).toBe(4)
+ })
+
+ it('should return 0 if no subarray meets the sum condition', () => {
+ const arr = [5, 6, 7]
+ const target = 3
+ const result = longestSubarrayWithSumAtMost(arr, target)
+ expect(result).toBe(0)
+ })
+})
diff --git a/Sliding-Windows/test/MaxSumSubarrayFixed.test.js b/Sliding-Windows/test/MaxSumSubarrayFixed.test.js
new file mode 100644
index 0000000000..d4ca107c65
--- /dev/null
+++ b/Sliding-Windows/test/MaxSumSubarrayFixed.test.js
@@ -0,0 +1,22 @@
+import { maxSumSubarrayFixed } from '../MaxSumSubarrayFixed'
+
+describe('Fixed-size Sliding Window - maxSumSubarrayFixed', () => {
+ it('should return the maximum sum of a subarray of size k', () => {
+ const arr = [2, 1, 5, 1, 3, 2]
+ const k = 3
+ const result = maxSumSubarrayFixed(arr, k)
+ expect(result).toBe(9)
+ })
+
+ it('should throw a RangeError if k is larger than the array length', () => {
+ const arr = [2, 1, 5]
+ const k = 4
+ expect(() => maxSumSubarrayFixed(arr, k)).toThrow(RangeError)
+ })
+
+ it('should throw a RangeError if k is less than 1', () => {
+ const arr = [2, 1, 5]
+ const k = 0
+ expect(() => maxSumSubarrayFixed(arr, k)).toThrow(RangeError)
+ })
+})
From a3c5ac035684dab66124b53961d6cf3e44e040a5 Mon Sep 17 00:00:00 2001
From: k7 <kesavanvel77@gmail.com>
Date: Tue, 5 Nov 2024 22:34:25 +0530
Subject: [PATCH 2/2] update directory file for sliding windows
---
DIRECTORY.md | 3 +++
1 file changed, 3 insertions(+)
diff --git a/DIRECTORY.md b/DIRECTORY.md
index 7f6484cae5..a29ece310e 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -322,6 +322,9 @@
* [StringSearch](Search/StringSearch.js)
* [TernarySearch](Search/TernarySearch.js)
* [UnionFind](Search/UnionFind.js)
+* **Sliding-Windows**
+ * [MaxSumSubarrayFixed](Sliding-Windows/MaxSumSubarrayFixed.js)
+ * [LongestSubarrayWithSumAtMost](Sliding-Windows/LongestSubarrayWithSumAtMost.js)
* **Sorts**
* [AlphaNumericalSort](Sorts/AlphaNumericalSort.js)
* [BeadSort](Sorts/BeadSort.js)