feat: leetcode 202

Author: 王洋

README.md

@@ -2,7 +2,7 @@
 
 <p align="center">
 <!-- TOPICS COUNT START -->
-<img src="https://img.shields.io/badge/-进度:183-green" alt="进度:183">
+<img src="https://img.shields.io/badge/-进度:184-green" alt="进度:184">
 <!-- 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/topics.json

@@ -899,6 +899,16 @@
     "url": "https://leetcode.cn/problems/number-of-1-bits/",
     "path": "./problemset/number-of-1-bits/README.md"
   },
+  {
+    "id": "202",
+    "title": {
+      "cn": "快乐数",
+      "en": "happy-number"
+    },
+    "difficulty": "简单",
+    "url": "https://leetcode.cn/problems/happy-number/description/",
+    "path": "./problemset/happy-number/README.md"
+  },
   {
     "id": "205",
     "title": {

assets/docs/TOPICS.md

@@ -180,6 +180,8 @@
 
 [191. 位1的个数](../../problemset/number-of-1-bits/README.md)
 
+[202. 快乐数](../../problemset/happy-number/README.md)
+
 [205. 同构字符串](../../problemset/isomorphic-strings/README.md)
 
 [206. 反转链表](../../problemset/reverse-linked-list/README.md)

problemset/happy-number/README.md

@@ -0,0 +1,38 @@
+# 快乐数
+
+> 难度：简单
+>
+> https://leetcode.cn/problems/happy-number/description/
+
+## 题目
+
+编写一个算法来判断一个数 n 是不是快乐数。
+
+「快乐数」 定义为：
+
+- 对于一个正整数，每一次将该数替换为它每个位置上的数字的平方和。
+- 然后重复这个过程直到这个数变为 1，也可能是 无限循环 但始终变不到 1。
+- 如果这个过程 结果为 1，那么这个数就是快乐数。
+
+如果 `n` 是 快乐数 就返回 `true` ；不是，则返回 `false` 。
+
+
+示例 1：
+```
+输入：n = 19
+输出：true
+解释：
+12 + 92 = 82
+82 + 22 = 68
+62 + 82 = 100
+12 + 02 + 02 = 1
+```
+
+示例 2：
+```
+输入：n = 2
+输出：false
+```
+
+提示：
+- 1 <= n <= 231 - 1

problemset/happy-number/index.py

@@ -0,0 +1,19 @@
+def isHappy(n: int) -> bool:
+  res = n == 1
+  arr = [n]
+  while n != 1:
+    sum = 0
+    for i in str(n):
+      sum += int(i) ** 2
+    if sum in arr:
+      break 
+    if sum == 1:
+      res = True 
+      break 
+    n = sum
+    arr.append(sum)
+  return res
+
+print(99, isHappy(99))
+print(19, isHappy(19))
+print(2, isHappy(2))

problemset/happy-number/index.spec.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from 'vitest'
+import { isHappy } from './index'
+
+describe('快乐数', () => {
+  testCase(isHappy)
+})
+
+function testCase(fn: (n: number) => boolean) {
+  it.each([
+    // test cases
+    [19, true],
+    [2, false],
+  ])('示例%#', (n, expected) => {
+    expect(fn(n)).toBe(expected)
+  })
+}

problemset/happy-number/index.ts

@@ -0,0 +1,20 @@
+export function isHappy(n: number): boolean {
+  let res: boolean = n === 1;
+  const arr: number[] = [n];
+  while (n !== 1) {
+    const sum = n.toString().split('').reduce((s, cur) => {
+      const curNum = Number(cur);
+      return s + curNum * curNum;
+    }, 0);
+    if (arr.includes(sum)) {
+      break;
+    }
+    if (sum === 1) {
+      res = true;
+      break;
+    }
+    arr.push(sum);
+    n = sum;
+  }
+  return res;
+}