feat: problems for the next week

Author: upupming

.eslintrc.js

@@ -6,17 +6,7 @@ module.exports = {
     project: './tsconfig.json'
   },
   rules: {
-    '@typescript-eslint/naming-convention': [
-      'error',
-      {
-        selector: 'interface',
-        format: ['PascalCase'],
-        custom: {
-          regex: '^I[A-Z]',
-          match: true
-        }
-      }
-    ],
+    '@typescript-eslint/naming-convention': 0,
     '@typescript-eslint/explicit-function-return-type': 0,
     '@typescript-eslint/strict-boolean-expressions': 0,
     'no-console': 0,

leetcode/残酷刷题/1146. Snapshot Array.ts

@@ -0,0 +1,44 @@
+class SnapshotArray {
+  // snap[i]: list of [snap_id, snap_value]
+  _snap: Array<Array<[number, number]>>
+  a: number[]
+  cnt = 0
+  changed: Set<number>
+  constructor (length: number) {
+    this._snap = Array(length).fill(0).map(() => [])
+    this.a = Array(length).fill(0)
+    this.changed = new Set(Array(length).fill(0).map((_, idx) => idx))
+  }
+
+  set (index: number, val: number): void {
+    this.a[index] = val
+    this.changed.add(index)
+  }
+
+  snap (): number {
+    for (const idx of this.changed) {
+      this._snap[idx].push([this.cnt, this.a[idx]])
+    }
+    this.changed.clear()
+    return this.cnt++
+  }
+
+  get (index: number, snap_id: number): number {
+    const n = this._snap[index].length
+    let l = 0; let r = n - 1
+    while (l < r) {
+      const mid = l + r + 1 >> 1
+      if (this._snap[index][mid][0] <= snap_id) l = mid
+      else r = mid - 1
+    }
+    return this._snap[index][l][1]
+  }
+}
+
+/**
+* Your SnapshotArray object will be instantiated and called as such:
+* var obj = new SnapshotArray(length)
+* obj.set(index,val)
+* var param_2 = obj.snap()
+* var param_3 = obj.get(index,snap_id)
+*/

leetcode/残酷刷题/1186. Maximum Subarray Sum with One Deletion.ts

@@ -0,0 +1,13 @@
+function maximumSum (arr: number[]): number {
+  const n = arr.length
+  // f[i][0]: not use deletion, f[i][1]: has used deletion
+  const f: number[][] = Array(n + 1).fill(0).map(() => [])
+  f[0][0] = f[0][1] = 0
+  let ans = -1e10
+  for (let i = 1; i <= n; i++) {
+    f[i][0] = Math.max(f[i - 1][0], 0) + arr[i - 1]
+    f[i][1] = Math.max(f[i - 1][1], f[i - 2]?.[0] ?? 0, 0) + arr[i - 1]
+    ans = Math.max(ans, f[i][0], f[i][1])
+  }
+  return ans
+};

leetcode/残酷刷题/152. Maximum Product Subarray.ts

@@ -0,0 +1,13 @@
+function maxProduct (nums: number[]): number {
+  const n = nums.length
+  // f[i][0]: max, f[i][1]: min; both ends with nums[i], as neg multiply neg can be pos
+  const f: number[][] = Array(n + 1).fill(0).map(() => [])
+  f[0][0] = f[0][1] = 1
+  let ans = -1e10
+  for (let i = 1; i <= n; i++) {
+    f[i][0] = Math.max(f[i - 1][0] * nums[i - 1], f[i - 1][1] * nums[i - 1], nums[i - 1])
+    f[i][1] = Math.min(f[i - 1][0] * nums[i - 1], f[i - 1][1] * nums[i - 1], nums[i - 1])
+    ans = Math.max(ans, f[i][0])
+  }
+  return ans
+};

leetcode/残酷刷题/2272. Substring With Largest Variance.ts

@@ -0,0 +1,34 @@
+function largestVariance (s: string): number {
+  const n = s.length
+  // 以 i 结尾的子数组的最大和
+  const f: number[] = Array(n + 1).fill(0)
+  // 以 i 结尾的并且一定包含 -1 的子数组的最大和
+  const g: number[] = Array(n + 1).fill(0)
+  let ans = 0
+  for (let i = 0; i < 26; i++) {
+    for (let j = 0; j < 26; j++) {
+      if (j === i) continue
+
+      f[0] = 0
+      g[0] = -1e10
+      for (let k = 1; k <= n; k++) {
+        const ch = s.charCodeAt(k - 1) - 'a'.charCodeAt(0)
+        if (ch === i) {
+          f[k] = Math.max(f[k - 1], 0) + 1
+          g[k] = g[k - 1] + 1
+        }
+        else if (ch === j) {
+          f[k] = Math.max(f[k - 1], 0) - 1
+          g[k] = Math.max(g[k - 1], f[k - 1], 0) - 1
+        }
+        else {
+          f[k] = f[k - 1]
+          g[k] = g[k - 1]
+        }
+
+        ans = Math.max(ans, g[k])
+      }
+    }
+  }
+  return ans
+};

leetcode/残酷刷题/2296. Design a Text Editor.ts

@@ -0,0 +1,73 @@
+export interface MyNode {
+  val: string
+  prev: MyNode | null
+  next: MyNode | null
+}
+
+class TextEditor {
+  cursor: MyNode
+  constructor () {
+    this.cursor = {
+      val: '#',
+      prev: null,
+      next: null
+    }
+  }
+
+  addText (text: string): void {
+    for (const ch of text) {
+      const newNode = {
+        val: ch,
+        prev: this.cursor,
+        next: this.cursor.next
+      }
+      if (this.cursor.next) this.cursor.next.prev = newNode
+      this.cursor.next = newNode
+      this.cursor = this.cursor.next
+    }
+  }
+
+  deleteText (k: number): number {
+    let cnt = 0
+    while (k-- && this.cursor.prev) {
+      this.cursor.prev.next = this.cursor.next
+      if (this.cursor.next) this.cursor.next.prev = this.cursor.prev
+      this.cursor = this.cursor.prev
+      cnt++
+    }
+    return cnt
+  }
+
+  getLast10 (): string {
+    let p: MyNode | null = this.cursor; let cnt = 10
+    const a = []
+    while (cnt-- && p && p.val !== '#') {
+      a.push(p.val)
+      p = p.prev
+    }
+    return a.reverse().join('')
+  }
+
+  cursorLeft (k: number): string {
+    while (k-- && this.cursor.prev) {
+      this.cursor = this.cursor.prev
+    }
+    return this.getLast10()
+  }
+
+  cursorRight (k: number): string {
+    while (k-- && this.cursor.next) {
+      this.cursor = this.cursor.next
+    }
+    return this.getLast10()
+  }
+}
+
+/**
+* Your TextEditor object will be instantiated and called as such:
+* var obj = new TextEditor()
+* obj.addText(text)
+* var param_2 = obj.deleteText(k)
+* var param_3 = obj.cursorLeft(k)
+* var param_4 = obj.cursorRight(k)
+*/

leetcode/残酷刷题/53. Maximum Subarray.ts

@@ -0,0 +1,10 @@
+function maxSubArray (nums: number[]): number {
+  const n = nums.length
+  const f = Array(n + 1).fill(0)
+  let ans = -1e10
+  for (let i = 1; i <= n; i++) {
+    f[i] = Math.max(f[i - 1], 0) + nums[i - 1]
+    ans = Math.max(ans, f[i])
+  }
+  return ans
+};