字节跳动笔试第四题，回溯

字节跳动第四题，回溯

num = list(input().strip())

lyst = [i for i in range(1,27)]
alpha = [i for i in range(65, 91)]
dyct = {str(lyst[i]): chr(alpha[i]) for i in range(len(lyst))}

def bt(num, tmp):
    if not num:
        res.append([tmp])
        return 
    if int(num[:1]) > 0:
        bt(num[1:], tmp+dyct[num[:1]])
    if len(num) > 1 and num[:2] in dyct:
        bt(num[2:], tmp+dyct[num[:2]])

res = []
bt(''.join(num), '')
res.sort()
for i in res:
    print(i[0])