题解 | #字符串排序#

s = input()
l = list(s)

words=[]


for i in range(len(l)):
    val=l[i]
    if 'a'<=val<='z' or 'A'<=val<='Z':
        words.append(val)
        l[i]=None
def quicksort(arr):
    if len(arr)<=1:
        return arr
    else:
        jizhun=ord(arr[0])%97%65
        left=[]
        right=[]
        mid=[]
        for val in arr:
            if ord(val)%97%65<jizhun:
                left.append(val)
            elif ord(val)%97%65>jizhun:
                right.append(val)
            else:
                mid.append(val)
        return quicksort(left)+mid+quicksort(right)
new_words=quicksort(words)
words=new_words
i=0
for val in l:
    if val==None:
        print(words[i],end="")
        i+=1
    else:
        print(val,end="")