Own Code:

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        arr_dict = {}
        result = []
        for item in arr:
            if arr_dict.get(f'{item}')  == None:
                arr_dict.update({f'{item}':1})
            else:
                arr_dict[f'{item}'] += 1
        
        for value in arr_dict.values():
            result.append(value)
        #print(arr_dict)
        return True if len(result) == len(set(result)) else False

Better Code:

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        count_dict = {}
        
        # 统计每个数字出现的次数
        for item in arr:
            count_dict[item] = count_dict.get(item, 0) + 1
        
        # 检查出现次数是否唯一
        return len(count_dict.values()) == len(set(count_dict.values()))