这题用python 几行就能ac啊 n = int(raw_put()) id_class = {} panding = '' for line  in range(n):     newline = raw_input().split('')         if newline[0] in id_class.keys():         panding = 'change'                 id_class[newline[0]] += [newline[1]]     else:         id_class[newline[0]] = [newline[1]] if panding == '':     print('YES') else:          new_sorted_data = sorted(id_class.items(),key = lambda x:x[0], reverse = False)     for i , j in new_sorted_data:         if len(j) != 1:             print(i+' '+' '.join(j)+'\n')