题解 | 字符串排序

s = input()

tmp = list()
for e in s:
    if e.isupper() or e.islower():
        tmp.append(e)
tmp.sort(key=lambda s: s.lower())

ans = list()
i = 0
for e in s:
    if not e.isupper() and not e.islower():
        ans.append(e)
    else:
        ans.append(tmp[i])
        i += 1

print(''.join(ans))