https://docs.python.org/zh-cn/3/tutorial/floatingpoint.html
why-0-point-1-does-not-exist-in-floating-point/
https://www.cnblogs.com/plwang1990/p/4146959.html
https://www.cnblogs.com/tsingke/p/10223183.html
https://zh.wikipedia.org/wiki/%E6%B5%AE%E7%82%B9%E6%95%B0
https://zh.wikipedia.org/wiki/%E7%A7%91%E5%AD%A6%E8%AE%B0%E6%95%B0%E6%B3%95
https://gis.stackexchange.com/a/359002/46277
Open OSGeo4W Shell as an administrator
Type py3_env in the console (This should print paths of your QGIS Python installation)
Type python -m pip install {your library}
“选项”--->“信任中心”--->“信任中心设置” ---> “打开或保存时显示隐藏标记”
禁用语法检查：
“文件 >> 选项”，打开选项设置窗口；
切换到 “校对” 选项，分别把 “键入时检查拼写” 和 “键入时标记语法错误” 左边的勾选去掉；
点击 “确定”，完成设置；此时，文档中不再提示语法错误。
https://en.wikipedia.org/wiki/15_puzzle
https://www.jaapsch.net/puzzles/fifteen.htm
https://www.jaapsch.net/puzzles/javascript/fifteenj.htm
https://link.springer.com/content/pdf/10.3758%2FBF03193214.pdf
https://github.com/MilanPecov/15-Puzzle-Solvers
上面的链接有个问题会出错，长时间给不出结果：
Puzzle([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 0], [13, 12, 14, 15]])
下面的程序给出了正确结果：
https://github.com/shahmk/15-puzzle-solver
./a.out 1 0102030405060708091011SS13121415
BFS USED
Expanded: 15675 nodes
Max Frontier: 16375 nodes
010203040506070809101112131415SS
path to solution: dllurdrulldrr
