topKFrequent 문제 풀이 추가

junzero741 · junzero741 · commit 00c625724784 · 2026-03-02T23:23:53.000+09:00
diff --git a/top-k-frequent-elements/junzero741.ts b/top-k-frequent-elements/junzero741.ts
@@ -0,0 +1,37 @@
+
+// TC: O(NlogN)
+// SC: O(N)
+function topKFrequent(nums: number[], k: number): number[] {
+    
+    /**
+    Map ( O(N) )
+    1 : 4
+    4 : 1
+    3 : 3
+    2 : 2 
+
+    -> convert it to array ( O(N) ) : [[1,4], [4,1], [3,3], [2,2]] 
+    -> sort by value ( O(NlogN) ): [[1,4], [3,3], [2,2], [4,1]]
+    -> slice(0,k) ( (O(N) ) : [[1,4], [3,3]] 
+    -> make array from keys ( (O(N) ) : [1,4]
+     */
+
+     const numMap = new Map<number, number>();
+     const n = nums.length;
+
+     for(let i = 0; i < n; i++) {
+        const num = nums[i];
+        const frequency = (numMap.get(num) || 0)
+        numMap.set(num, frequency + 1);
+     }
+
+
+    const numFrequencyArr = Array.from(numMap);
+    const sortedNumFrequencyKeysArr = 
+        numFrequencyArr
+            .sort((a,b) => b[1]-a[1])
+            .map((entry) => entry[0]);
+    
+
+     return sortedNumFrequencyKeysArr.slice(0, k)
+};
