独一无二的出现次数-哈希表1207-python

没看答案，首先利用哈希表统计元素出现次数，然后对次数进行排序，最后查验是否出现了重复。

from collections import defaultdict

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        freq = defaultdict(int)
        for num in arr:
            freq[num] += 1

        freq = sorted(freq.items(), key=lambda x:x[1], reverse=True)
        n = len(freq)

        for i in range(1, n):
            if freq[i][1] == freq[i-1][1]:
                return False
        
        return True

首先利用哈希表统计元素出现次数，然后利用新的哈希表对次数进行统计，并不断查验是否出现了重复。

from collections import defaultdict

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        freq_arr = defaultdict(int)
        freq_freq = dict()

        for num in arr:
            freq_arr[num] += 1

        for fq in freq_arr.values():
            if fq in freq_freq.keys():
                return False
            else:
                freq_freq[fq] = 1
        
        return True