题解 | #字符统计#
字符统计
http://www.nowcoder.com/practice/c1f9561de1e240099bdb904765da9ad0
用字典做
num=input()
num1=sorted(set(num))
dict1=dict.fromkeys(num1,0)
ans=''
for i in num:
dict1[i]+=1
lst=sorted(dict1.items(),key=lambda x:x[1],reverse=True)
for item in lst:
ans+=item[0]
print(ans)
