题解 | 字符串排序

# s = input().strip()
# # 提取所有字母
# letters = [c for c in s if c.isalpha()]
# # 按小写字母排序（保持稳定排序，相同字母大小写按原顺序）
# sorted_letters = sorted(letters, key=lambda x: x.lower())
# # 构建结果列表
# result = list(s)
# idx = 0
# for i in range(len(result)):
#     if result[i].isalpha():
#         result[i] = sorted_letters[idx]
#         idx += 1
# # 输出结果
# print("".join(result))

s = input().strip()
letters = [c for c in s if c.isalpha()]
sorted_letters = sorted(letters,key=lambda x: x.upper())
result = list(s)
idx = 0
for i in range(len(result)):
    if result[i].isalpha():
        result[i]=sorted_letters[idx]
        idx += 1
print(''.join(result))