131 lines
2.9 KiB
Python
131 lines
2.9 KiB
Python
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import sys
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input = open("input", 'r')
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# input = open("sample", 'r')
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data = []
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total = 0
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mypos = (0, 0)
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epos = (0, 0)
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x = 0
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y = 0
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for line in input:
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data.append([])
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x = 0
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for c in line.strip():
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if c == "S":
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mypos = (x, y)
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data[y].append(ord("a") - ord("a"))
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elif c == "E":
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epos = (x, y)
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data[y].append(ord("z") - ord("a"))
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else:
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data[y].append(ord(c) - ord("a"))
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x += 1
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y += 1
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move = [(0, -1), (0, 1), (1, 0), (-1, 0)]
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def dijkstras(m, start):
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unvisited = []
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for y in range(len(m)):
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for x in range(len(m[0])):
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unvisited.append((x,y))
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sp = {}
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pn = {}
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max_value = sys.maxsize
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for node in unvisited:
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sp[node] = max_value
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sp[start] = 0
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while unvisited:
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cmn = None
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for pos in unvisited:
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if cmn == None:
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cmn = pos
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elif sp[pos] < sp[cmn]:
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cmn = pos
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neighbors = []
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for side in move:
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newPos = (cmn[0] + side[0], cmn[1] + side[1])
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if newPos[0] < 0 or newPos[0] >= len(m[0]):
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continue
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elif newPos[1] < 0 or newPos[1] >= len(m):
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continue
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posV = m[cmn[1]][cmn[0]]
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nposV = m[newPos[1]][newPos[0]]
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if posV + 1 >= nposV:
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neighbors.append(newPos)
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for neighbor in neighbors:
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tv = sp[cmn] + 1
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if tv < sp[neighbor]:
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sp[neighbor] = tv
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pn[neighbor] = cmn
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unvisited.remove(cmn)
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return pn, sp
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pn, sp = dijkstras(data, mypos)
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print(sp[epos])
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aStarts = []
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move = [(0, -1), (0, 1), (1, 0), (-1, 0)]
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def dijkstras_rev(m, start):
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unvisited = []
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for y in range(len(m)):
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for x in range(len(m[0])):
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unvisited.append((x,y))
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sp = {}
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pn = {}
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max_value = sys.maxsize
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for node in unvisited:
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sp[node] = max_value
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sp[start] = 0
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while unvisited:
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cmn = None
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for pos in unvisited:
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if cmn == None:
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cmn = pos
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elif sp[pos] < sp[cmn]:
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cmn = pos
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neighbors = []
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for side in move:
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newPos = (cmn[0] + side[0], cmn[1] + side[1])
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if newPos[0] < 0 or newPos[0] >= len(m[0]):
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continue
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elif newPos[1] < 0 or newPos[1] >= len(m):
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continue
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posV = m[cmn[1]][cmn[0]]
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nposV = m[newPos[1]][newPos[0]]
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if posV - 1 <= nposV:
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neighbors.append(newPos)
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for neighbor in neighbors:
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tv = sp[cmn] + 1
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if tv < sp[neighbor]:
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sp[neighbor] = tv
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pn[neighbor] = cmn
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unvisited.remove(cmn)
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return pn, sp
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pn, sp = dijkstras_rev(data, epos)
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aMin = []
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for key in sp:
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if data[key[1]][key[0]] == 0:
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aMin.append(sp[key])
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print(min(aMin))
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