feat: top k frequent elements

Author: minji-go

top-k-frequent-elements/minji-go.java

@@ -0,0 +1,18 @@
+class Solution {
+    public int[] topKFrequent(int[] nums, int k) {
+        Map<Integer, Integer> count = new HashMap<>();
+        for(int num : nums){
+            count.put(num, count.getOrDefault(num, 0)+1);
+        }
+        List<Integer> tops = count.keySet().stream()
+                .sorted((i1, i2) -> count.get(i2)-count.get(i1))
+                .limit(k)
+                .toList();
+
+        int[] answer = new int[k];
+        for(int i=0; i<k; i++) {
+            answer[i] = tops.get(i);
+        }
+        return answer;
+    }
+}