Create yeongu.cpp

Author: YeonguChoe

top-k-frequent-elements/yeongu.cpp

@@ -0,0 +1,30 @@
+// TC: O(n logn)
+// SC: O(n)
+
+vector<int> topKFrequent(vector<int>& nums, int k) {
+    unordered_map<int, int> frequency;
+    for (int n : nums) {
+        frequency[n] += 1;
+    }
+    auto comparator = [&frequency](int n1, int n2) {
+        return frequency[n1] > frequency[n2];
+    };
+
+    priority_queue<int, vector<int>, decltype(comparator)> min_heap(
+        comparator);
+
+    for (auto& entry : frequency) {
+        min_heap.push(entry.first);
+        if (min_heap.size() > k) {
+            min_heap.pop();
+        }
+    }
+
+    vector<int> output;
+
+    for (int i = 0; i < k; i++) {
+        output.push_back(min_heap.top());
+        min_heap.pop();
+    }
+    return output;
+}