From dd4515a68b4e4f32b473b72c475ee7099520fd31 Mon Sep 17 00:00:00 2001
From: Luo <82520819+Jerry-306@users.noreply.github.com>
Date: Tue, 12 Oct 2021 14:50:44 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=201207=20=E7=8B=AC=E4=B8=80?=
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---
 problems/1207.独一无二的出现次数.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/problems/1207.独一无二的出现次数.md b/problems/1207.独一无二的出现次数.md
index a65b26e6..808ff9f8 100644
--- a/problems/1207.独一无二的出现次数.md
+++ b/problems/1207.独一无二的出现次数.md
@@ -119,6 +119,7 @@ Go：
 
 JavaScript：
 ``` javascript
+// 方法一：使用数组记录元素出现次数
 var uniqueOccurrences = function(arr) {
     const count = new Array(2002).fill(0);// -1000 <= arr[i] <= 1000
     for(let i = 0; i < arr.length; i++){
@@ -134,6 +135,21 @@ var uniqueOccurrences = function(arr) {
     }
     return true;
 };
+
+// 方法二：使用Map 和 Set
+/**
+ * @param {number[]} arr
+ * @return {boolean}
+ */
+var uniqueOccurrences = function(arr) {
+    // 记录每个元素出现次数
+    let map = new Map();
+    arr.forEach( x => {
+        map.set(x, (map.get(x) || 0) + 1); 
+    })
+    // Set() 里的元素是不重复的。如果有元素出现次数相同，则最后的set的长度不等于map的长度
+    return map.size === new Set(map.values()).size
+};
 ```
 
 -----------------------