feat: leetcode 剑指 Offer II 091

Author: deweyou

README.md

@@ -2,7 +2,7 @@
 
 <p align="center">
 <!-- TOPICS COUNT START -->
-<img src="https://img.shields.io/badge/-进度:412-green" alt="进度:412">
+<img src="https://img.shields.io/badge/-进度:413-green" alt="进度:413">
 <!-- TOPICS COUNT END -->
 <a href="./assets/docs/TOPICS.md"><img src="https://img.shields.io/badge/-题库目录-blue" alt="题库目录"></a>
 <a href="./assets/docs/CATEGORIES.md"><img src="https://img.shields.io/badge/-题库分类-red" alt="题库分类"></a>

assets/data/categories.json

@@ -1386,6 +1386,12 @@
         "title": "适合打劫银行的日子",
         "path": "./problemset/find-good-days-to-rob-the-bank/README.md",
         "difficulty": "中等"
+      },
+      {
+        "id": "剑指 Offer II 091",
+        "title": "粉刷房子",
+        "path": "./problemset/paint-house/README.md",
+        "difficulty": "中等"
       }
     ]
   },

assets/data/topics.json

@@ -4118,5 +4118,15 @@
     "difficulty": "中等",
     "url": "https://leetcode.cn/problems/4ueAj6/",
     "path": "./problemset/sorted-circular-linked-list/README.md"
+  },
+  {
+    "id": "剑指 Offer II 091",
+    "title": {
+      "cn": "粉刷房子",
+      "en": "paint-house"
+    },
+    "difficulty": "中等",
+    "url": "https://leetcode.cn/problems/JEj789/",
+    "path": "./problemset/paint-house/README.md"
   }
 ]

assets/docs/CATEGORIES.md

@@ -264,6 +264,7 @@
 | 926. [将字符串翻转到单调递增](../../problemset/flip-string-to-monotone-increasing/README.md) | 中等 |
 | 1994. [好子集的数目](../../problemset/the-number-of-good-subsets/README.md) | 困难 |
 | 2100. [适合打劫银行的日子](../../problemset/find-good-days-to-rob-the-bank/README.md) | 中等 |
+| 剑指 Offer II 091. [粉刷房子](../../problemset/paint-house/README.md) | 中等 |
 
 ## 双指针
 

assets/docs/TOPICS.md

@@ -822,4 +822,6 @@
 
 [剑指 Offer II 114. 外星文字典](../../problemset/alien-dictionary/README.md)
 
-[剑指 Offer II 029. 排序的循环链表](../../problemset/sorted-circular-linked-list/README.md)
+[剑指 Offer II 029. 排序的循环链表](../../problemset/sorted-circular-linked-list/README.md)
+
+[剑指 Offer II 091. 粉刷房子](../../problemset/paint-house/README.md)

problemset/paint-house/README.md

@@ -0,0 +1,61 @@
+# 粉刷房子
+
+> 难度：中等
+>
+> https://leetcode.cn/problems/JEj789/
+
+## 题目
+
+假如有一排房子，共 `n` 个，每个房子可以被粉刷成红色、蓝色或者绿色这三种颜色中的一种，你需要粉刷所有的房子并且使其相邻的两个房子颜色不能相同。
+
+当然，因为市场上不同颜色油漆的价格不同，所以房子粉刷成不同颜色的花费成本也是不同的。每个房子粉刷成不同颜色的花费是以一个 `n x 3` 的正整数矩阵 `costs` 来表示的。
+
+例如，`costs[0][0]` 表示第 `0` 号房子粉刷成红色的成本花费；`costs[1][2]` 表示第 `1` 号房子粉刷成绿色的花费，以此类推。
+
+请计算出粉刷完所有房子最少的花费成本。
+
+### 示例
+
+#### 示例 1：
+
+```
+输入: costs = [[17,2,17],[16,16,5],[14,3,19]]
+输出: 10
+解释: 将 0 号房子粉刷成蓝色，1 号房子粉刷成绿色，2 号房子粉刷成蓝色。
+     最少花费: 2 + 5 + 3 = 10。
+```
+
+#### 示例 2：
+
+```
+输入: costs = [[7,6,2]]
+输出: 2
+```
+
+## 解题
+
+```ts 
+/**
+ * 动态规划
+ * @desc 时间复杂度 O(N)  空间复杂度 O(1)
+ * @param costs
+ * @returns
+ */
+export function minCost(costs: number[][]): number {
+  const len = costs.length
+  let dp = [...costs[0]]
+
+  for (let i = 1; i < len; i++) {
+    const newDp = [0, 0, 0]
+    for (let j = 0; j < 3; j++) {
+      newDp[j] = Math.min(
+        dp[(j + 1) % 3],
+        dp[(j + 2) % 3],
+      ) + costs[i][j]
+    }
+    dp = newDp
+  }
+
+  return Math.min(...dp)
+}
+```

problemset/paint-house/index.spec.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it } from 'vitest'
+import { minCost } from '.'
+
+describe('粉刷房子', () => {
+  testCase(minCost)
+})
+
+function testCase(fn: (costs: number[][]) => number) {
+  it.each([
+    [
+      [[17, 2, 17], [16, 16, 5], [14, 3, 19]],
+      10,
+    ],
+    [
+      [[7, 6, 2]],
+      2,
+    ],
+  ])('示例%#', (costs, expected) => {
+    expect(fn(costs)).toBe(expected)
+  })
+}

problemset/paint-house/index.ts

@@ -0,0 +1,23 @@
+/**
+ * 动态规划
+ * @desc 时间复杂度 O(N)  空间复杂度 O(1)
+ * @param costs
+ * @returns
+ */
+export function minCost(costs: number[][]): number {
+  const len = costs.length
+  let dp = [...costs[0]]
+
+  for (let i = 1; i < len; i++) {
+    const newDp = [0, 0, 0]
+    for (let j = 0; j < 3; j++) {
+      newDp[j] = Math.min(
+        dp[(j + 1) % 3],
+        dp[(j + 2) % 3],
+      ) + costs[i][j]
+    }
+    dp = newDp
+  }
+
+  return Math.min(...dp)
+}