Feat: add solution for 217

Author: HC-kang

contains-duplicate/HC-kang.ts

@@ -0,0 +1,19 @@
+/**
+217. Contains Duplicate
+
+Example 1:
+Input: nums = [1,2,3,1]
+Output: true
+
+Example 2:
+Input: nums = [1,2,3,4]
+Output: false
+
+Example 3:
+Input: nums = [1,1,1,3,3,4,3,2,4,2]
+Output: true
+ */
+
+function containsDuplicate(nums: number[]): boolean {
+  return nums.length !== new Set(nums).size;
+}