ambrus,
The only notable difference between the two is this thread deals with the shortest bridge/ladder as requested by Ieronim while the QoTW allows any length bridge/ladder. If you see the benchmarks in the thread, we optimized the heck out of it.
Like Daniel Martin notes in the analysis of the qotw solutions, many of the solutions (though not mine) found the shortest ladder even though the task didn't ask for that. This is no wonder: qotw is a friendly list where the intent is to learn rather than to compete.