The v-line Format for Outputting Solutions

The new v-line format introduced in 2022 will be used. An example v-line in the current format is: v 011011000110001111 This is equivalent to v -1 2 3 -4 5 6 -7 -8 -9 10 11 -12 -13 -14 15 16 17 18 in the pre-2022 format. That is, the line start with 'v ' and is followed by the solution as a bitstring, where the i'th bit gives the value (0 or 1) assigned to variable having the index i.