Python Challenge (level 24)

佘小宝的爹

URI:http://www.pythonchallenge.com/pc/hex/ambiguity.html
Username: butter; password: fly
说明:
--
解题方法
# Copyright for the following five classes by John Eriksson
# <http://arainyday.se/>, 2006. Originally written for the AStar
# library <http://www.pygame.org/projects/9/195/> and released into the
# public domain. Thanks a lot!

import Image

class Path:
def __init__ (self, nodes, totalCost):
self.nodes = nodes
self.totalCost = totalCost
def getNodes (self):
return self.nodes
def getTotalMoveCost (self):
return self.totalCost

class Node:
def __init__ (self, location, mCost, lid, parent = None):
self.location = location
self.mCost = mCost
self.parent = parent
self.score = 0
self.lid = lid
def __eq__ (self, n):
if n.lid == self.lid:
return 1
else:
return 0

class AStar:
def __init__ (self, maphandler):
self.mh = maphandler
def _getBestOpenNode (self):
bestNode = None
for n in self.on:
if not bestNode:
bestNode = n
elif n.score <= bestNode.score:
bestNode = n
return bestNode
def _tracePath (self, n):
nodes = []
totalCost = n.mCost
p = n.parent
nodes.insert(0, n)
while True:
if p.parent is None:
break
nodes.insert(0, p)
p = p.parent
return Path(nodes, totalCost)
def _handleNode (self, node, end):
i = self.o.index(node.lid)
self.on.pop(i)
self.o.pop(i)
self.c.append(node.lid)
nodes = self.mh.getAdjacentNodes(node, end)
for n in nodes:
if n.location == end:
return n
elif n.lid in self.c:
continue
elif n.lid in self.o:
i = self.o.index(n.lid)
on = self.on;
if n.mCost < on.mCost:
self.on.pop(i);
self.o.pop(i);
self.on.append(n);
self.o.append(n.lid);
else:
self.on.append(n);
self.o.append(n.lid);
return None
def findPath (self, fromlocation, tolocation):
self.o = []
self.on = []
self.c = []
end = tolocation
fnode = self.mh.getNode(fromlocation)
self.on.append(fnode)
self.o.append(fnode.lid)
nextNode = fnode
while nextNode is not None:
finish = self._handleNode(nextNode, end)
if finish:
return self._tracePath(finish)
nextNode=self._getBestOpenNode()
return None

class SQ_Location:
def __init__ (self, x, y):
self.x = x
self.y = y
def __eq__ (self, l):
if l.x == self.x and l.y == self.y:
return 1
else:
return 0

class SQ_MapHandler:
def __init__ (self, mapdata, width, height):
self.m = mapdata
self.w = width
self.h = height
def getNode (self, location):
x = location.x
y = location.y
if x < 0 or x >= self.w or y < 0 or y >= self.h:
return None
d = self.m[(y * self.w) + x]
if d == -1:
return None
return Node(location, d, ((y * self.w) + x));
def getAdjacentNodes (self, curnode, dest):
result = []
cl = curnode.location
dl = dest
n = self._handleNode(cl.x + 1, cl.y, curnode, dl.x, dl.y)
if n:
result.append(n)
n = self._handleNode(cl.x - 1, cl.y, curnode, dl.x, dl.y)
if n:
result.append(n)
n = self._handleNode(cl.x, cl.y + 1, curnode, dl.x, dl.y)
if n:
result.append(n)
n = self._handleNode(cl.x, cl.y - 1, curnode, dl.x, dl.y)
if n:
result.append(n)
return result
def _handleNode (self, x, y, fromnode, destx, desty):
n = self.getNode(SQ_Location(x, y))
if n is not None:
dx = max(x, destx) - min(x, destx)
dy = max(y, desty) - min(y, desty)
emCost = dx+dy
n.mCost += fromnode.mCost
n.score = n.mCost + emCost
n.parent = fromnode
return n
return None

def main ():
img = Image.open("maze.png")
maze = img.load()
mapdata = []
# Translate pixel data into something that AStar understands.
for elt in img.getdata():
if elt == (255, 255, 255, 255):
mapdata.append(-1)
else:
mapdata.append(1)
# Define start and destination points.
mapdata[639] = 5
mapdata[410241] = 6
astar = AStar(SQ_MapHandler(mapdata, 641, 641))
start = SQ_Location(639, 0)
end = SQ_Location(1, 640)
p = astar.findPath(start, end)
data = []
# Extract data from "logs".
for node in p.nodes:
if node.location.x % 2 and node.location.y % 2:
data.append(chr(maze[node.location.x, node.location.y][0]))
h = open("unzip-me.zip", "wb")
h.write("".join(data))
h.close()

if __name__ == "__main__":
main()
过关答案:
lake