Lem-in: Shortest Path Isn't Always the Goal (opens in new tab)

My team just started lem-in, the next project after Groupie Tracker. You've got a colony of rooms and tunnels, a pile of ants at ##start, and the job is to get them all to ##end as fast as possible. My first thought was "easy, just BFS for the shortest path." Turns out that's the wrong instinct. Say the shortest path is 5 rooms long and you've got 50 ants. Send them all down that one path and they queue up single-file, taking way more turns than you'd think. But if there's a second, slightly ...