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Labyrinth optimal solution in Clear category for Open Labyrinth by nickie
from heapq import heappush, heappop
def checkio(maze):
q = []
heappush(q, (0, (1, 1)))
prev = dict()
prev[(1, 1)] = None
while q:
moves, (i, j) = heappop(q)
if i == 10 and j == 10:
break
for (di, dj, move) in [(0,1,'E'), (1,0,'S'), (-1,0,'N'), (0,-1,'W')]:
if maze[i+di][j+dj] == 0 and (i+di, j+dj) not in prev:
prev[(i+di, j+dj)] = (i, j, move)
heappush(q, (moves+1, (i+di, j+dj)))
answer = []
i = 10
j = 10
while prev[(i, j)] != None:
(i, j, move) = prev[(i, j)]
answer.append(move)
answer.reverse()
return ''.join(answer)
#This code using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
print(checkio([
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1],
[1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]))
#be careful with infinity loop
print(checkio([
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
]))
print(checkio([
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
]))
print(checkio([
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1],
[1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1],
[1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1],
[1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
]))
Oct. 9, 2013
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