5 ms·
Well it's not really fun nor a puzzle, they simply can't pass each other, and the dispatcher will have to look for the next suitable sidings.
by m2fkxy 4y ago
Well it's not really fun nor a puzzle, they simply can't pass each other, and the dispatcher will have to look for the next suitable sidings.
- eesmith 4y agoAs a puzzle, suppose ABC is going that way -> and and 123 is going <- that way, each 3 miles long, broken into segments A/B/C and 1/2/3, respectively. Let '-' be the siding, able to hold a mile-long set of cars. ABC ... 123 `-' Move C into _, uncouple from AB, and back AB to return to the mainline. AB ... 123 `C' Move AB and 123 to the left, past the siding: AB123 ... `C' Uncouple 1, move 23 into the siding to couple to C, and return C to the mainline: AB1 ... 23C `-' Uncouple 23 from C, pick up 1, and move back to the right side of the siding: AB ... 123.C `-' You've now gotten C past 123. Repeat with B then A, leaving the track as 123 ... ABC. This solution limits the maximum length to 3 miles. A 4 mile long solution would keep 1 coupled to 23 while moving C from the siding back to the mainline.