Add solution: top K frequent elements

algocode/hash_tables/top_k_frequent_elements.py

@@ -0,0 +1,30 @@
+from typing import List
+from collections import defaultdict
+
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        res = []
+        count_elems = defaultdict(int)
+        count_in = { i: set() for i in range(0, len(nums) + 1) }
+        for i in range(0, len(nums)):
+            cur_char = nums[i]
+            count_elems[cur_char] += 1
+            tmp_value = count_elems[cur_char]
+            count_in[tmp_value].add(cur_char)
+            count_in[tmp_value - 1].discard(cur_char)
+        # Начинаем обход count_in с самого большого значения вхождений 
+        for i in range(len(nums), 0, -1):
+            # Если есть элементы - записываем их в массив res
+            while len(count_in[i]) > 0:
+                res.append(count_in[i].pop())
+                # Уменьшаем значение k
+                k -=1
+                if k == 0:
+                    return res
+        return res
+        
+cl = Solution()
+print(cl.topKFrequent(nums=[1,1,1,2,2,3], k = 2))
+print(cl.topKFrequent(nums=[1], k = 1))
+print(cl.topKFrequent(nums = [1,2,1,2,1,2,3,1,3,2], k = 2))
+