Feat | NeetCode | Roadmap | #20 Sliding Window Maximum

README.md

@@ -90,4 +90,5 @@
   - [Task #16](src/neetcode/sliding-window/longest-substring-without-repeating-characters) – _Longest Substring Without Repeating Characters_ - _[check the task](https://neetcode.io/problems/longest-substring-without-duplicates)_
   - [Task #17](src/neetcode/sliding-window/longest-repeating-character-replacement) – _Longest Repeating Character Replacement_ - _[check the task](https://neetcode.io/problems/longest-repeating-substring-with-replacement)_
   - [Task #17](src/neetcode/sliding-window/longest-repeating-character-replacement) – _Longest Repeating Character Replacement_ - _[check the task](https://neetcode.io/problems/longest-repeating-substring-with-replacement)_
-  - [Task #19](src/neetcode/sliding-window/minimum-window-substring) – _Minimum Window Substring_ - _[check the task](https://neetcode.io/problems/minimum-window-with-characters)_
+  - [Task #19](src/neetcode/sliding-window/minimum-window-substring) – _Minimum Window Substring_ - _[check the task](https://neetcode.io/problems/minimum-window-with-characters)_
+  - [Task #20](src/neetcode/sliding-window/sliding-window-maximum) – _Sliding Window Maximum_ - _[check the task](https://neetcode.io/problems/sliding-window-maximum)_

src/neetcode/sliding-window/sliding-window-maximum/solution.test.ts

@@ -0,0 +1,11 @@
+import { maxSlidingWindow } from './solution';
+
+describe('Sliding Window Maximum | NeetCode | RoadMap | Testcases', () => {
+  test('#1 Example', () => {
+    const nums = [1, 2, 1, 0, 4, 2, 6];
+    const k = 3;
+    const expected = [2, 2, 4, 4, 6];
+    const output = maxSlidingWindow(nums, k);
+    expect(output).toEqual(expected);
+  });
+});

src/neetcode/sliding-window/sliding-window-maximum/solution.ts

@@ -0,0 +1,37 @@
+/**
+ * @param {number[]} nums - an array of integers
+ * @param {number} k - integer
+ * @return {number[]} a list that contains the maximum element in the sliding window at each step.
+ * The window of size `k` starts at the left edge of the array slides one position to the right until
+ * it reaches the right edge of the array.
+ */
+export const maxSlidingWindow = (nums: number[], k: number): number[] => {
+  const n = nums.length;
+  const leftMax = new Array<number>(n);
+  const rightMax = new Array<number>(n);
+
+  leftMax[0] = nums[0];
+  rightMax[n - 1] = nums[n - 1];
+
+  for (let i = 1; i < n; i++) {
+    if (i % k === 0) {
+      leftMax[i] = nums[i];
+    } else {
+      leftMax[i] = Math.max(leftMax[i - 1], nums[i]);
+    }
+
+    if ((n - 1 - i) % k === 0) {
+      rightMax[n - 1 - i] = nums[n - 1 - i];
+    } else {
+      rightMax[n - 1 - i] = Math.max(rightMax[n - i], nums[n - 1 - i]);
+    }
+  }
+
+  const output = new Array<number>(n - k + 1);
+
+  for (let i = 0; i < n - k + 1; i++) {
+    output[i] = Math.max(leftMax[i + k - 1], rightMax[i]);
+  }
+
+  return output;
+};