Splitting into Two Groups#802
An unusual situation occurred with the polar explorers: it was decided to establish a new station nearby, and experienced explorers are rare. Therefore, all polar explorers at this station should be divided into two parts, with one part sent to the new station. However, there is a complication: some explorers have formed such strong bonds that they refuse to work at different stations. Each group of explorers insists on working together or not at all.
Help divide these groups into two parts that are as equal in size as possible (i.e., the absolute difference in the number of explorers between the two parts should be minimized), while keeping each group intact. Both parts must contain at least one group.
The first line contains the integer (2 \le n \le 30000), the number of groups. The second line contains positive integers, each indicating the number of people in a group. The total number of explorers across all groups does not exceed .
On the first line, print the sizes of the two parts.
On the second and third lines, list the group numbers assigned to the first and second parts, respectively (groups are numbered in the order they appear in the input, starting from one). If there are multiple valid solutions, any of them may be provided.
Example 1