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guanghechenguanghechen
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🎨 [BREAKING] feat: rewrite '@algorithm.ts/sliding-window'
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Diff for: ‎_fixtures/leetcode/sliding-window-maximum/data.json

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[
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{
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"input": [[1, 3, -1, -3, 5, 3, 6, 7], 3],
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"answer": [3, 3, 5, 5, 6, 7]
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},
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{
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"input": [[1], 1],
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"answer": [1]
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},
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{
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"input": [[1, -1], 1],
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"answer": [1, -1]
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},
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{
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"input": [[9, 11], 2],
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"answer": [11]
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},
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{
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"input": [[4, -2], 2],
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"answer": [4]
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}
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]

Diff for: ‎packages/sliding-window/README.md

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@@ -78,27 +78,24 @@ A typescript implementation of the **sliding-window** algorithm.
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* `SlidingWindow`
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81-
Member | Return | Description
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:----------------------------:|:---------:|:---------------------------------------
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`init(WINDOW_SIZE?: number)` | `void` | Initialize a sliding window.
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`push(idx: number)` | `void` | See a new element with index `idx`.
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`max()` | `number` | Get the index of the maximum value in the sliding window.
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Member | Return | Description
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:----------------------------------------------:|:---------:|:---------------------------------------
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`init(WINDOW_SIZE: number, startIdx?: number)` | `void` | Initialize a sliding window.
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`moveForward(steps: number)` | `void` | Move the sliding window forward with specified steps.
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`max()` | `number` | Get the index of the maximum value in the sliding window.
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* `createSlidingWindow`
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```typescript
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export function createSlidingWindow(
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_WINDOW_SIZE: number,
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cmp: (x: number, y: number) => -1 | 0 | 1 | number,
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): SlidingWindow
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export function createSlidingWindow(cmp: (x: number, y: number) => -1 | 0 | 1 | number): ISlidingWindow
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```
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- `createSlidingWindow(5, (x, y) => nums[x] - nums[y])`:
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Create a sliding window with a fixed width of 5, and maintain the index of
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- `createSlidingWindow((x, y) => nums[x] - nums[y])`:
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Create a sliding window (the window size is not specified yet), and maintain the index of
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the nums with the largest value in the window.
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- The `slidingWindow.max(10, (x, y) => nums[y] - nums[x])`:
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Create a sliding window with a fixed width of 10, and maintain the index of
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- The `createSlidingWindow((x, y) => nums[y] - nums[x])`:
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Create a sliding window (the window size is not specified yet), and maintain the index of
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the nums with the smallest value in the window.
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104101

@@ -114,13 +111,12 @@ A typescript implementation of the **sliding-window** algorithm.
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if (N < K) return []
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const results: number[] = []
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const window = createSlidingWindow(K, (x, y) => nums[x] - nums[y])
118-
window.init()
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120-
for (let i = 0, _end = K - 1; i < _end; ++i) window.push(i)
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const window = createSlidingWindow((x, y) => nums[x] - nums[y])
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window.init(K)
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window.moveForward(K - 1)
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for (let i = K - 1; i < N; ++i) {
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window.push(i)
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window.moveForward()
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results.push(nums[window.max()])
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}
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return results

Diff for: ‎packages/sliding-window/__test__/leetcode.sliding-window-maximum.spec.ts

-53
This file was deleted.

Diff for: ‎packages/sliding-window/__test__/oj/sliding-window-maximum.ts

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import { createSlidingWindow } from '../../src'
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export default maxSlidingWindow
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export function maxSlidingWindow(nums: number[], K: number): number[] {
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const N = nums.length
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if (N < K) return []
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const results: number[] = []
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const window = createSlidingWindow((x, y) => nums[x] - nums[y])
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window.init(K)
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window.moveForward(K - 1)
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for (let i = K - 1; i < N; ++i) {
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window.moveForward()
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results.push(nums[window.max()])
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}
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return results
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}

Diff for: ‎packages/sliding-window/__test__/sliding-window.spec.ts

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import { testOjCodes } from 'jest.setup'
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import { createSlidingWindow } from '../src'
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describe('basic', function () {
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test('simple', function () {
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const elements: number[] = [1, 9, 3, 5, 4, 7, 6, 8, 2]
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const f = (idx: number): number => elements[idx]
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const slidingWindow = createSlidingWindow((idx: number, idy: number) => f(idx) - f(idy))
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slidingWindow.init(3)
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slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(1)
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slidingWindow.moveForward(2)
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expect(f(slidingWindow.max())).toEqual(9)
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slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(9)
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slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(5)
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24+
slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(7)
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27+
slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(7)
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30+
slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(8)
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slidingWindow.moveForward()
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expect(f(slidingWindow.max())).toEqual(8)
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})
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})
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38+
describe('oj', function () {
39+
// https://leetcode.com/problems/sliding-window-maximum/
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testOjCodes('leetcode/sliding-window-maximum', import('./oj/sliding-window-maximum'))
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})

Diff for: ‎packages/sliding-window/src/index.ts

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@@ -7,13 +7,12 @@ export interface ISlidingWindow {
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* Initialize a sliding window.
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* @param WINDOW_SIZE
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*/
10-
init(WINDOW_SIZE?: number): void
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init(WINDOW_SIZE: number, startIdx?: number): void
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1212
/**
13-
* See a new element with index `idx`.
14-
* @param idx
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* Move the sliding window forward with specified steps.
1514
*/
16-
push(idx: number): void
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moveForward(steps?: number): void
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1817
/**
1918
* Get the index of the maximum value in the sliding window.
@@ -29,32 +28,35 @@ export interface ISlidingWindow {
2928
* @param cmp
3029
*/
3130
export function createSlidingWindow(
32-
_WINDOW_SIZE: number,
3331
cmp: (x: number, y: number) => -1 | 0 | 1 | number,
3432
): ISlidingWindow {
35-
let front = 0
36-
let end = -1
37-
let WINDOW_SIZE: number = _WINDOW_SIZE
33+
let front: number
34+
let end: number
35+
let idx: number
36+
let WINDOW_SIZE: number
3837
const window: number[] = []
39-
return { init, push, max }
38+
return { init, moveForward, max }
4039

41-
function init(_WINDOW_SIZE?: number): void {
42-
if (_WINDOW_SIZE != null) WINDOW_SIZE = _WINDOW_SIZE
40+
function init(_WINDOW_SIZE: number, startIdx = 0): void {
41+
WINDOW_SIZE = Math.max(1, _WINDOW_SIZE)
4342
window.length = 0
4443
front = 0
4544
end = -1
45+
idx = startIdx
4646
}
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48-
function push(idx: number): void {
49-
if (front <= end && idx - window[front] >= WINDOW_SIZE) front += 1
48+
function moveForward(steps = 1): void {
49+
for (let i = 0; i < steps; ++i) {
50+
if (front <= end && idx - window[front] >= WINDOW_SIZE) front += 1
5051

51-
for (; front <= end; end -= 1) {
52-
const delta: number = cmp(window[end], idx)
53-
if (delta > 0) break
54-
}
52+
for (; front <= end; end -= 1) {
53+
const delta: number = cmp(window[end], idx)
54+
if (delta > 0) break
55+
}
5556

56-
// eslint-disable-next-line no-plusplus
57-
window[++end] = idx
57+
// eslint-disable-next-line no-plusplus
58+
window[++end] = idx++
59+
}
5860
}
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6062
function max(): number {

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