131 lines
3.3 KiB
Python
Executable file
131 lines
3.3 KiB
Python
Executable file
#!/usr/bin/env python
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# 2021 - Advent Of Code - 9 part 2
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def parse_file(file):
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hmap = []
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with open(file, encoding="utf-8") as f:
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for line in f.readlines():
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linemap = []
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for n in line.strip():
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linemap.append(int(n))
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hmap.append(linemap)
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return hmap
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def find_lowpoints(hmap):
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# pylint: disable=R0912
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lpoints = []
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# first line
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x = 0
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y = 0
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if hmap[y][x] < hmap[y][x + 1] and hmap[y][x] < hmap[y + 1][x]:
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lpoints.append([x, y])
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for x in range(1, len(hmap[y]) - 1):
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v = hmap[y][x]
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if v < hmap[y][x - 1] and v < hmap[y][x + 1] and v < hmap[y + 1][x]:
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lpoints.append([x, y])
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x = len(hmap[y]) - 1
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if hmap[y][x] < hmap[y][x - 1] and hmap[y][x] < hmap[y + 1][x]:
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lpoints.append([x, y])
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# middle lines
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for y in range(1, len(hmap) - 1):
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x = 0
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if hmap[y][x] < hmap[y][x + 1] and hmap[y][x] < hmap[y - 1][x] and hmap[y][x] < hmap[y + 1][x]:
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lpoints.append([x, y])
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for x in range(1, len(hmap[y]) - 1):
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v = hmap[y][x]
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if v < hmap[y][x - 1] and v < hmap[y][x + 1] and v < hmap[y - 1][x] and v < hmap[y + 1][x]:
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lpoints.append([x, y])
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x = len(hmap[y]) - 1
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if hmap[y][x] < hmap[y][x - 1] and hmap[y][x] < hmap[y - 1][x] and hmap[y][x] < hmap[y + 1][x]:
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lpoints.append([x, y])
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# last line
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y = len(hmap) - 1
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x = 0
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if hmap[y][x] < hmap[y][x + 1] and hmap[y][x] < hmap[y - 1][x]:
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lpoints.append([x, y])
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for x in range(1, len(hmap[y]) - 1):
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v = hmap[y][x]
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if v < hmap[y][x - 1] and v < hmap[y][x + 1] and v < hmap[y - 1][x]:
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lpoints.append([x, y])
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x = len(hmap[y]) - 1
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if hmap[y][x] < hmap[y][x - 1] and hmap[y][x] < hmap[y - 1][x]:
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lpoints.append([x, y])
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return lpoints
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def find_basin(hmap, bpoints, point):
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bpoints.append(point)
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# print(f'bpoints: {bpoints}')
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x = point[0]
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y = point[1]
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# halt if edge, already in list or value is 9
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# up
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if y > 0:
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if hmap[y-1][x] != 9:
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if [x, y-1] not in bpoints:
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find_basin(hmap, bpoints, [x, y-1])
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# down
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if y < len(hmap) - 1:
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if hmap[y+1][x] != 9:
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if [x, y+1] not in bpoints:
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find_basin(hmap, bpoints, [x, y+1])
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# left
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if x > 0:
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if hmap[y][x-1] != 9:
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if [x-1, y] not in bpoints:
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find_basin(hmap, bpoints, [x-1, y])
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# right
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if x < len(hmap[y]) - 1:
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if hmap[y][x+1] != 9:
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if [x+1, y] not in bpoints:
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find_basin(hmap, bpoints, [x+1, y])
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return bpoints
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# heightmap = parse_file('input_example.txt')
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heightmap = parse_file('input.txt')
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# print_hmap(heightmap)
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low_points = find_lowpoints(heightmap)
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risk_levels = 0
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basins = []
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for p in low_points:
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basins_points = []
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find_basin(heightmap, basins_points, p)
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basins.append(basins_points)
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sizes = [0] * len(basins)
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i = 0
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for b in basins:
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size = 0
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for p in b:
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size += 1
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sizes[i] = size
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i += 1
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# 3 biggest basins
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biggest_basins = sorted(zip(sizes, basins))[-3:]
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product = 1
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for s, b in biggest_basins:
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print(f'basin size: {s}')
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product *= s
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print(f'product: {product}')
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