Halloween treats#3840
Every year, the same problem arises at Halloween: each neighbour is only willing to give a certain total number of sweets on that day, regardless of how many children visit them. As a result, a child might get nothing if they arrive too late. To avoid conflicts, the children have decided to pool all the sweets they collect and then divide them evenly among themselves. From last year's Halloween, they know how many sweets they will get from each neighbour. Since they care more about fairness than the total number of sweets they receive, they want to select a subset of neighbours to visit such that, after sharing, every child gets the same number of sweets. They will not be satisfied if any sweets are left over.
Your task is to help the children and provide a solution.
The input consists of several test cases. The first line of each test case contains two integers and (1 \leq c \leq n \leq 100\,000), the number of children and the number of neighbours, respectively. The next line contains space-separated integers a_1, \ldots, a_n (1 \leq a_i \leq 100\,000), where a_i represents the number of sweets the children will get if they visit neighbour .
The last test case is followed by a line containing two zeros.
For each test case, output one line with the indices of the neighbours the children should visit (here, index corresponds to neighbour who gives a total number of a_i sweets). If it is not possible to choose neighbours so that every child receives at least one sweet, print "no sweets". If there are several solutions where each child receives at least one sweet, you may print any of them.
Мысал 1