cjh (07/18/82)
Efficient traversal without having to check the walls is easy; in a 5-high room (the biggest you'll get on a standard (80 x 24) screen) simply move in a horizontal zigzag (keys ununun or ybybyb) then retrace the edge of the territory you've covered. you'll still hit traps infrequently but they're probably so well-concealed that it would take too much time to find them. In 4-high rooms the simple zigzag works, and in 2- or 3-high a straight line. If you're looking for a door on a long wall you can do intermittent jogs (lunlun or lnulnu or hybhyb or hbyhby) in a 4-high; in other rooms just move along the wall. The assumption around here is that all squares adjacent to you are searched with equal efficiency, although I've never seen solid evidence. Thus you can search for doors on long walls with fewer keystrokes by jumping (after you've checked for traps), e.g. 3s3l3s3l. Obviously searching for a door on a short wall at the other end of the screen loses if you have a wall almost as short and nearby; this is enough of a judgment/guesswork call that I've never tried to make it concrete. So far as I know, Murphy's law is the wrong thing to depend on even with the pseudo-random number generator of UNIX. Taking your "notions" in order: 1. As far as I know, the chance of finding a door \when you are within [sight] of it/ is unrelated to the length of the wall it's in; this means that it will tend to take more absolute time to find a door on a long wall. 2. see above 3. I have \\never// found a secret door on the first level. I have found traps, which suggests that the probability of a secret door may actually be 0 rather than just very small. 4. I usually give up looking for a door after 27 searches total searches over the adjacent squares; this is based on cumulative unquantified experience. Unfortunately there's always a chance that you could take indefinitely long to find a secret door, just as you could be a 10th-level character with 21 hit points; at least searching, so far as I know, doesn't have the capability to generate its own closed loop a la Floating Eye paralysis. 5. Unless you're getting really stuck for food you should always find all the rooms on a level; you know there are 3 x 3 rooms and you can always give apparently dead-end corridors a little extra search. Of course, it's quite possible that you won't be able to get into all of the rooms on a level, due to strategic placement of trap doors (or teleport traps, if you're low on food).
cjh (07/18/82)
Aside from the general sloppiness of my previous essay, there was one specific howler; I should have said 3x3 room-equivalents (or 3x3 [room]s).