contains duplicate solution

Author: JangAyeon

contains-duplicate/JangAyeon.js

@@ -0,0 +1,19 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+
+// 첫번째 제출
+var containsDuplicate = function (nums) {
+  const counter = new Map();
+  for (let e of nums) {
+    const v = counter.has(e) ? counter.get(e) + 1 : 1;
+    counter.set(e, v);
+  }
+  const answer = [...counter.values()].some((item) => item >= 2);
+  return answer;
+};
+// 두번째 제출
+var containsDuplicate = function (nums) {
+  return new Set(nums).size !== nums.length;
+};