题解 | 回文数索引

t = int(input())
for _ in range(t):
    s = input()
    if s == s[::-1]:
        print(-1)
    else:
        for i in range(len(s)):
            if i == 0 and s[1:] == s[1:][::-1]:
                print(0)
            elif i == len(s) - 1 and s[:-1] == s[:-1][::-1]:
                print(len(s) - 1)
            else:
                if s[:i] + s[i + 1 :] == s[i + 1 :][::-1] + s[:i][::-1]:
                    print(i)
        

            

python