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80 lines
2.9 KiB
80 lines
2.9 KiB
3 years ago
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from queue import PriorityQueue
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import sys
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class grid:
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def __init__(self):
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self.y = []
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self.attempts = 0
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self.solutions = []
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self.current_smallest_solution_level = None
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self.point_costs = {(0, 0): 0}
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self.next_point_queue = PriorityQueue()
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self.next_point_queue.put((0, (0, 0)))
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def addline(self, line):
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self.y.append([int(i) for i in line])
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self.maxy = len(self.y) - 1
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self.maxx = len(self.y[0]) - 1
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# print(self.maxx)
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# print(self.maxy)
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def findpath(self):
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while not self.next_point_queue.empty():
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level, poi = self.next_point_queue.get()
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self.attempts += 1
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if self.attempts % 100000 == 0:
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print('Attempt %d, solutions: %d, cost: %d' % (self.attempts, len(self.solutions), self.current_smallest_solution_level or -1))
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neighbors = self.get_neighbors(poi)
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for i in neighbors:
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next_level = level + int(self.y[i[0]][i[1]])
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if (self.current_smallest_solution_level is not None and
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next_level > self.current_smallest_solution_level):
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# We already found a solution that was overall less risky
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# than the current path, so who cares.
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continue
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if i == (self.maxy, self.maxx):
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self.solutions.append(next_level)
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if (self.current_smallest_solution_level is None or
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next_level < self.current_smallest_solution_level):
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self.current_smallest_solution_level = next_level
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# print('Found solution: ', i, ', orig level ', level)
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continue
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elif i in self.point_costs and self.point_costs[i] < next_level:
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# We already visited the point on a cheaper path.
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continue
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else:
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# print('Path: %s, next: %s' % (repr(path), i))
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self.point_costs[i] = next_level
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self.next_point_queue.put((next_level, i))
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def get_neighbors(self, poi):
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nex = {}
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rv = []
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if poi[0] != self.maxy:
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nex.setdefault(self.y[poi[0] + 1][poi[1]], list()).append((poi[0] + 1, poi[1]))
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if poi[1] != self.maxx:
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nex.setdefault(self.y[poi[0]][poi[1] + 1], list()).append((poi[0], poi[1] + 1))
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if poi[0] != 0:
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nex.setdefault(self.y[poi[0] - 1][poi[1]], list()).append((poi[0] - 1, poi[1]))
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if poi[1] != 0:
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nex.setdefault(self.y[poi[0]][poi[1] - 1], list()).append((poi[0], poi[1] - 1))
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order = sorted(nex.keys())
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for j in order:
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rv += nex[j]
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return rv
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gri = grid()
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with open(sys.argv[1], 'r') as f:
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for i in f.readlines():
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gri.addline(i.strip())
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gri.findpath()
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print(min(gri.solutions))
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