54 lines
1.4 KiB
Python
54 lines
1.4 KiB
Python
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import sys
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def main():
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lines = [line.rstrip() for line in sys.stdin]
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nc = len(lines[0])
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nr = len(lines)
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m = [list(map(int, line)) for line in lines]
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# Part 1
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low_points = []
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rlevels = 0
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for x, row in enumerate(m):
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for y, val in enumerate(row):
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if (
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(x == 0 or m[x - 1][y] > val)
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and (x == nr - 1 or m[x + 1][y] > val)
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and (y == 0 or m[x][y - 1] > val)
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and (y == nc - 1 or m[x][y + 1] > val)
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):
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low_points.append((x, y)) # for part 2
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rlevels += val + 1
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print(rlevels)
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# Part 2
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basins = [expand_basin(m, (x, y), nc, nr) for x, y in low_points]
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a, b, c = sorted(map(len, basins))[-3:]
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print(a * b * c)
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def expand_basin(m, start, nc, nr):
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basin = []
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sx, sy = start
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explo = [(sx, sy)]
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while explo:
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pos = explo.pop(0)
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x, y = pos
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if m[x][y] == 9:
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continue
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basin.append(pos)
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if x > 0 and (n := (x - 1, y)) not in basin and n not in explo:
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explo.append(n)
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if x < nr - 1 and (n := (x + 1, y)) not in basin and n not in explo:
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explo.append(n)
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if y > 0 and (n := (x, y - 1)) not in basin and n not in explo:
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explo.append(n)
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if y < nc - 1 and (n := (x, y + 1)) not in basin and n not in explo:
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explo.append(n)
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return basin
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if __name__ == "__main__":
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main()
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