84 lines
2.3 KiB
Python
Executable file
84 lines
2.3 KiB
Python
Executable file
#!/usr/bin/env python
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# 2021 - Advent Of Code - 9
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def parse_file(file):
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hmap = []
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with open(file) 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 print_hmap(hmap):
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for y in range(len(hmap)):
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for x in range(len(hmap[y])):
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print(hmap[y][x], end='')
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print()
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def find_lowpoints(hmap):
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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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# 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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for p in low_points:
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print(f'low point at {p}, value {heightmap[p[1]][p[0]]}')
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risk_levels += heightmap[p[1]][p[0]] + 1
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print(f'The sum of risk levels is {risk_levels}')
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