Wrong answer with secondary_columns

[xxzl0130]

When I set secondary_columns, it can not produce the correct answer. Example is here. The problem can be reproduced with input file M2-6-2.json, here "optional": 2 means secondary_columns=2. Also you can directly use map.txt as input of your example program. The answer should be 44, and one of them is with rows [0, 26, 12, 39, 41, 2, 3]