题解 | 字符串处理

while True:
    try:
        s = input()
        ans1, ans2 = [], []
        visited = set()
        for i in range(len(s)):
            c = s[i].lower()
            if c not in visited:
                ans2.append(s[i])
                visited.add(c)
            ans1.append(s[i])
            if i != len(s) - 1 and s[i].isalpha() != s[i + 1].isalpha():
                ans1.append('_')
        print(''.join(ans1))
        print(''.join(ans2))
    except:
        break