n-puzzle @ 42 fremont

usage: solver.py [-h] [-c] [-ida] [-g] [-u]
                 [-f {hamming,gaschnig,manhattan,conflicts}]
                 [-s {zero_first,zero_last,snail}] [-p] [-v]
                 file

n-puzzle @ 42 fremont

positional arguments:
  file                  input file

optional arguments:
  -h, --help            show this help message and exit
  -c                    colors
  -ida                  ida* search
  -g                    greedy search
  -u                    uniform-cost search
  -f {hamming,gaschnig,manhattan,conflicts}
                        heuristic function
  -s {zero_first,zero_last,snail}
                        solved state
  -p                    pretty print solution steps
  -v                    gui visualizer

search:

default search is A*

• fast and efficient
• memory heavy

or use -ida for IDA*

• light on memory
• slower than a*

input puzzle configurations:

-s zero_first (blank tile first)

4
00 01 02 03
04 05 06 07
08 09 10 11
12 13 14 15

-s zero_last (blank tile last)

4
01 02 03 04
05 06 07 08
09 10 11 12
13 14 15 00

-s snail (default, spiral pattern)

4
01 02 03 04
12 13 14 05
11 00 15 06
10 09 08 07

heuristics:

-f hamming hamming distance aka "tiles out of place"

-f gaschnig performs better than hamming distance

-f manhattan manhattan distance heuristic (default)

-f conflicts linear conflicts usually more informed than manhattan distance

miscellaneous:

-g greedy search: ignores the g(n) in A* formula f(n) = g(n) + h(n), quickly finds a suboptimal solution

-u uniform cost search: discards the h(n) in A* formula (turns off heuristics and becomes dijkstra's, slow)

-c colors in terminal output

-p pretty print solution steps

-v replay solution steps in graphical visualizer