题解 | 字符串排序

s = input()
rec = []
for id, c in enumerate(s):
    if c.isalpha():
        rec.append([c, id])
# 按忽略大小写的新字母排序，字母相同时按出现顺序排序
sorted_cs = sorted(rec, key=lambda x: (x[0].lower(), x[1]))
j = 0
result = []
for i in range(len(s)):
    if s[i].isalpha():
        result.append(sorted_cs[j][0])
        j += 1
    else:
        result.append(s[i])
print("".join(result))