Add a (mostly) English README and a map from Wind Fantasy Nexus

README.EN.md

@@ -0,0 +1,259 @@
+A sokoban game solver
+===========================
+This project proposed a AI solver for sokoban (japanese for warehouse keeper) which is a difficult computational problem. The algorithm being used consisted of BFS (breadth first search), DFS (depth first search), UCS (uniform cost search) and A* (A star search).
+
+## ToC
+
+* [0. Getting started](#0)
+* [1. Overview](#1)
+* [2. Evaluation](#2)
+
+<a id="0"></a>
+## 0. Overview
+
+1. The following libraries are needed：`sys`，`collections`，`numpy`，`heapq`，`time`.
+2. (`numpy` requires separate installation, while the other ones are installed with a default Python installation).
+
+3. Run `sokoban.py` in your local environment.
+
+### Usage
+
+```
+$ python sokoban.py --help
+```
+```
+Usage: sokoban.py [options]
+
+Options:
+  -h, --help            show this help message and exit
+  -l SOKOBANLEVELS, --level=SOKOBANLEVELS
+                        level of game to play (test1-10.txt, level1-5.txt)
+  -m AGENTMETHOD, --method=AGENTMETHOD
+                        research method (bfs, dfs, ucs, astar)
+```
+
+`-l`：There are several set of maps included. Include ".txt" in the parameter. 
+`-m`：Valid options include `bfs`，`dfs`，`ucs`, and `astar`.
+
+### Examples
+
+```
+$ python sokoban.py -l test1.txt -m bfs
+```
+```
+rUUdRdrUUluL
+Runtime of bfs: 0.15 second.
+```
+The first line indicates the action taken by the actor，where `u`，`d`，`l`，`r indicate up, down, left, or right movements，
+The corresponding capital letter indicates the movement in corresponding direction WHILE PUSHING AGAINST THE BOS.
+The second line includes the total run time.
+
+<a id="1"></a>
+## 1. Overview
+
+Sokoban is the [Box Pusher Game](https://www.mathsisfun.com/games/sokoban.html)，where a player moves acrosds a map and pushes
+boxes to designated spots on the map.
+
+### Example（`level1.txt`）
+
+**Visualized：**
+
+![](./img/level1.png)
+
+**Input：**
+
+```
+  #####
+###   #
+#.&B  #
+### B.#
+#.##B #
+# # . ##
+#B XBB.#
+#   .  #
+######## 
+```
+
+Where `#` represent the wall，`.` is the destination(s)，`B` is the box(es）（`X` indicates that it's already in place),
+`&` is the actor/protagonist（`%` if overlaps with one of the destination），and whitespaces are unoccupied spaces the actor can move into.
+
+### Method
+
+搜索算法在这里的使用，简单理解就是当前状态下推箱者采取一个可能动作后，产生下一状态，以此类推，直到最终状态为结束状态。既然用到的是搜索算法，首先要确定的是state space graph（SSG）和search tree（ST）。如果直接把输入的整个地图作为SSG存储在数据结构中，会使内存的占用随搜索的进行而飙升，所以必须重新定义新的SSG，既能减少空间占用，又能代表足够的信息。在推箱子这个问题中，其实关键的部分仅为箱子的位置和人的位置，因为墙和目的地的位置都是不变的。所以定义SSG的样式如下所示，其中第一个tuple代表当前人的坐标，第二个tuple代表当前箱子的坐标。
+
+```
+((2, 2), ((2, 3), (3, 4), (4, 4), (6, 1), (6, 4), (6, 5)))
+```
+
+而ST就是当前SSG基于推箱者可行的动作进行分枝，每一个动作都会导致新的不同的SSG产生，最终形成很多个branch和node。只要所有箱子的坐标和目的地的坐标完全契合，就说明游戏结束（胜利）。但推箱子游戏，往往会把箱子推到一些位置，比如说死角，这种局面其实也会导致游戏结束（失败），就没有继续走下去的必要了。因此，利用这些导致死局的pattern可以帮助我们修剪树（prune tree），使分裂的node减少许多，进而减少内存的占用。下图展示一些死局的pattern，以一个箱子为中心，如果周围一圈内出现这些情况，则说明该当前态没有再分裂下去的必要了。
+
+![](./img/dead_patterns.jpg)
+
+另外为了避免推箱者做无意义的移动，比如不推箱子来回晃悠，我们要让每次分枝后的SSG与同一条分枝上的SSG不重复，即某个“人的位置和所有箱子的位置”不能重复出现。
+
+然后就是算法的部分，BFS和DFS就不多说了，一个“每条路都走一小步慢慢走”，一个”一条路走到死再走下一条“。而UCS加入了cost function，就是”挑最节省成本的路走“，这里的cost function定义为：到目当前状态为止，所有没推着箱子走的步数。这样能够激励推箱者尽可能做有意义的移动，而不是不推箱子逛该。最后A*，在cost function上加入heuristic function，目的是激励推箱者不单去推箱子，并且还要把箱子推往目的地。这里的heuristic function用的是manhatten distance，定义为：到目当前状态为止，所有箱子按顺序排列的位置和所有目的地按顺序排列的位置，两两间的manhatten distance总和。
+
+<a id="2"></a>
+## 2. Evaluated
+
+* BFS：
+
+```
+$ python sokoban.py -l test1.txt -m bfs
+rUUdRdrUUluL
+Runtime of bfs: 0.15 second.
+
+$ python sokoban.py -l test1.txt -m bfs
+rUUdRdrUUluL
+Runtime of bfs: 0.13 second.
+
+$ python sokoban.py -l test2.txt -m bfs
+UUddrrrUU
+Runtime of bfs: 0.01 second.
+
+$ python sokoban.py -l test3.txt -m bfs
+LrdrddDLdllUUdR
+Runtime of bfs: 0.27 second.
+
+$ python sokoban.py -l test4.txt -m bfs
+llldRRR
+Runtime of bfs: 0.01 second.
+
+test5.txt: more than 1 minute.
+
+$ python sokoban.py -l test6.txt -m bfs
+dlluRdrUUUddrruuulL
+Runtime of bfs: 0.02 second.
+
+$ python sokoban.py -l test7.txt -m bfs
+LUUUluRddddLdlUUUUluR
+Runtime of bfs: 1.25 second.
+
+$ python sokoban.py -l test8.txt -m bfs
+llDDDDDDldddrruuLuuuuuuurrdLulDDDDDDlllddrrUdlluurRdddrruuLUUUUUUluRdddddddrddlluUdlluurRdrUUUUUU
+Runtime of bfs: 0.30 second.
+
+$ python sokoban.py -l level1.txt -m bfs
+RurrddddlDRuuuuLLLrdRDrddlLdllUUdR
+Runtime of bfs: 35.04 second.
+```
+
+* DFS：
+
+```
+$ python sokoban.py -l test1.txt -m dfs
+rrUrdllluRRlldrrrUlllururrDLrullldRldrrUruLrdllldrrdrUlllurrurDluLrrdllldrrdrUU
+Runtime of dfs: 0.09 second.
+
+$ python sokoban.py -l test2.txt -m dfs
+rrrUlldlUrrrUlldrrdllluU
+Runtime of dfs: 0.01 second.
+
+$ python sokoban.py -l test3.txt -m dfs
+rrdldrdllDRlldlUrrrdrruLrdllLrrrululldRllldRlurrrdrruLrdllUrrdllLrrrullllldRRRlllurrrrrdLrulllllUdrrrrrdlLrrullllldrRRlllurrrrrdLrullluRldrrrdlLrrullllldrRRlllurrrrrdLrulllururulluLrrrdlddldrrrdlLrrullllldrRRlllurrrrrdLrulUlldrrrdlLrrullllldrRRlllurrrrrdLrulllurrUldrdrdlLrrullllldrRRlllurrrrrdLrulllurrululurrDDldldrrrdlLrrulllururDlldrdrruLrdllLrrrululldRllldRlurrrdLrrruLrdlllulldRRRlllurrurrdrdLrulL
+Runtime of dfs: 0.36 second.
+
+$ python sokoban.py -l test4.txt -m dfs
+rrrdllllLrrrrrdllllllluRRRR
+Runtime of dfs: 0.01 second.
+
+test5.txt: more than 1 minute.
+
+$ python sokoban.py -l test6.txt -m dfs
+rrdlllluRRlldrrrruLrdllUUUddrrdlllluuuurRlldddrrrruuuLL
+Runtime of dfs: 0.02 second.
+
+$ python sokoban.py -l test7.txt -m dfs
+rdllllurRlldrrrruulLrrdLrdllllurRlldrrrruullLrrrdLrdllllurRlldrrrruulluulldDrrrrdLrdllllUrdrrrulLrrdlllluUrrrrdllLrrrullllUdrrrrdllldlUrrrrulluululldRRllurrrrrdddllldrrrdlllluUrrrruuullllldrDDrrrrdllldlUrrrrulluUlllurrRllldrrrddrrdllllUrrrruuuLrdddllllUdrruuluRllldRRllurrrDllddrrrruuuLrdddlllluurrDDrrdlLrrdlllluRRlldrrrruulllluuruRllldrrrddrrdLrdllllurRlldrrrruuuuuLrdddlllldrrdrUrdllllurrulluuruRllldrrrddlldrrrruLrdllllurRlldrrrruuuuLrdddLrdlllluuuruRllldrrrdDrruuuLrdddlllluuruRllldrrrddrrdlLrrdlllluurrrruuuLrdddllllddrrrrullLrrrdllllUrrrrulluulldDrrrruuulLrrdddlllluulurRRllldrrrddrrdllldlUrrrruuuuLrdddllldrrrdlllluUrrrruuulLrrdddlluulllurRRllldrrrddrrdlllluUdrrrruuuLrdddlllluUruRldrddrrdlllluuuluR
+Runtime of dfs: 0.78 second.
+
+$ python sokoban.py -l test8.txt -m dfs
+llDlurrrdLrullldRDDDDDlllddrrdrruuLrddllulluurrruuuuulurrrdLrullldRdddddlllddrrUruLruuuuulurrrdLrullDDDDDDlddlluuRRllddrrdrruuLrddllulluurrDrUldrrddllUlluurrrUdlllddrrUruLruUddldrrddllulluuRlddrrdrruuluLruuUdddldrrddllulluuRlddrrdrruuluLruuuUddddldrrddllulluuRlddrrdrruuluLruuuuUluRldrdddddldrrddllulluuRRllddrrdrruulUUUUUU
+Runtime of dfs: 0.11 second.
+
+level1.txt: more than 1 minute.
+```
+
+* UCS：
+
+```
+$ python sokoban.py -l test1.txt -m ucs
+rURdrUUlLdlU
+Runtime of ucs: 0.09 second.
+
+$ python sokoban.py -l test2.txt -m ucs
+UUddrrrUU
+Runtime of ucs: 0.01 second.
+
+$ python sokoban.py -l test3.txt -m ucs
+LrdrddDLdllUUdR
+Runtime of ucs: 0.17 second.
+
+$ python sokoban.py -l test4.txt -m ucs
+llldRRR
+Runtime of ucs: 0.01 second.
+
+test5.txt: more than 1 minute.
+
+$ python sokoban.py -l test6.txt -m ucs
+dlluRdrUUUddrruuulL
+Runtime of ucs: 0.02 second.
+
+$ python sokoban.py -l test7.txt -m ucs
+LUUUluRddddLdlUUUUluR
+Runtime of ucs: 0.94 second.
+
+$ python sokoban.py -l test8.txt -m ucs
+llDDDDDDldddrruuLuuuuuuurrdLulDDDDDDlllddrrUdlluurRdddrruuLUUUUUUluRdddddddrddlluUdlluurRdrUUUUUU
+Runtime of ucs: 0.31 second.
+
+$ python sokoban.py -l level1.txt -m ucs
+RurrddddlDRuuuuLLLrdRDrddlLdllUUdR
+Runtime of ucs: 33.22 second.
+```
+
+* A star
+
+```
+$ python sokoban.py -l test1.txt -m astar
+rUUdRdrUUluL
+Runtime of astar: 0.01 second.
+
+$ python sokoban.py -l test2.txt -m astar
+UUddrrrUU
+Runtime of astar: 0.01 second.
+
+$ python sokoban.py -l test3.txt -m astar
+LrdrddDLdllUUdR
+Runtime of astar: 0.01 second.
+
+$ python sokoban.py -l test4.txt -m astar
+llldRRR
+Runtime of astar: 0.00 second.
+
+$ python sokoban.py -l test5.txt -m astar
+uruLdlUURUdRdrUUllLdlU
+Runtime of astar: 0.11 second.
+
+$ python sokoban.py -l test6.txt -m astar
+dlluRdrUUUddrruuulL
+Runtime of astar: 0.02 second.
+
+$ python sokoban.py -l test7.txt -m astar
+LUUUluRddddLdlUUUUluR
+Runtime of astar: 0.16 second.
+
+$ python sokoban.py -l test8.txt -m astar
+llDDDDDDldddrruuLuuuuuuurrdLulDDDDDDlllddrrUdlluurRdddrruuLUUUUUUluRdddddddrddlluUdlluurRdrUUUUUU
+Runtime of astar: 0.33 second.
+
+$ python sokoban.py -l level1.txt -m astar
+RurrdLLLrrrdddlDRlLdllUUdRRurruuulldRDrddL
+Runtime of astar: 0.85 second.
+```
+
+表现最好的是A*。BFS、UCS和A*输出的推箱者动作一致，DFS虽然也能找到解决方式但会出现逛该现象，显然其他方法会让结果更简单一些。后续可以提升的方面有：
+
+* 定义更简单的SSG
+* 更加全面的dead pattern
+* 更加适合的cost function和heuristic function

sokobanLevels/windFantasyNexusElvesFoggyMine1.txt

@@ -0,0 +1,9 @@
+    #### 
+ ####  #
+## B   #
+#  # #B#
+#.&..  ##
+## # #  #
+##   B  #
+##  #####
+#####