add Top K Frequent Elements solution

Author: HoonDongKang

top-k-frequent-elements/HoonDongKang.ts

@@ -0,0 +1,22 @@
+/**
+ * [Problem]: [347] Top K Frequent Elements
+ * (https://leetcode.com/problems/top-k-frequent-elements/description/)
+ */
+
+function topKFrequent(nums: number[], k: number): number[] {
+    // 시간복잡도 O(nlogn)
+    // 공간복잡도 O(n)
+    function mapFun(nums: number[], k: number): number[] {
+        const frequentMap = new Map<number, number>();
+
+        for (let i = 0; i < nums.length; i++) {
+            frequentMap.set(nums[i], (frequentMap.get(nums[i]) || 0) + 1);
+        }
+
+        const sorted = Array.from(frequentMap.entries()).sort((a, b) => b[1] - a[1]);
+
+        return sorted.slice(0, k).map(([num]) => num);
+    }
+
+    return mapFun(nums, k);
+}