From 3f16de6462d9d80bf44ec8d0adc95988fccbd028 Mon Sep 17 00:00:00 2001
From: "qingyi.liu" <qingyi.liu@17zuoye.com>
Date: Wed, 19 May 2021 11:42:18 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E7=AC=AC202=E9=A2=98.=20?=
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---
 problems/0202.快乐数.md | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/problems/0202.快乐数.md b/problems/0202.快乐数.md
index 8c0dd1e7..90228b8c 100644
--- a/problems/0202.快乐数.md
+++ b/problems/0202.快乐数.md
@@ -112,6 +112,40 @@ Python：
 
 Go：
 
+javaScript:
+
+```js
+function getN(n) {
+    if (n == 1 || n == 0) return n;
+    let res = 0;
+    while (n) {
+        res += (n % 10) * (n % 10);
+        n = parseInt(n / 10);
+    }
+    return res;
+}
+
+var isHappy = function(n) {
+    const sumSet = new Set();
+    while (n != 1 && !sumSet.has(n)) {
+        sumSet.add(n);
+        n = getN(n);
+    }
+    return n == 1;
+};
+
+// 使用环形链表的思想 说明出现闭环 退出循环
+var isHappy = function(n) {
+    if (getN(n) == 1) return true;
+    let a = getN(n), b = getN(getN(n));
+    // 如果 a === b 
+    while (b !== 1 && getN(b) !== 1 && a !== b) {
+        a = getN(a);
+        b = getN(getN(b));
+    }
+    return b === 1 || getN(b) === 1 ;
+};
+```