104 lines
2.8 KiB
Python
104 lines
2.8 KiB
Python
#!/usr/bin/env python3
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# N
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# NW NO
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# W X O
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# SW SO
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# S
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from collections import defaultdict
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import math
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freqmap = defaultdict(list)
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lx = 0
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ly = 0
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with open("day08") as f:
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for y,l in enumerate(f):
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ly += 1
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lx = len(l.strip())
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for x,c in enumerate(l.strip()):
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if c != '.':
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freqmap[c].append((y,x))
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antinodes = set()
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for (_, coords) in freqmap.items():
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for s,a in enumerate(coords):
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for b in coords[s+1:]:
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dy = abs(a[0]-b[0])
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dx = abs(a[1]-b[1])
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# vertical
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if a[1]==b[1] and a[0]<b[0]:
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antinodes.add((a[0]-dy,a[1]))
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antinodes.add((b[0]+dy,b[1]))
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if a[1]==b[1] and a[0]>b[0]:
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antinodes.add((a[0]+dy,a[1]))
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antinodes.add((b[0]-dy,b[1]))
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# horizontal
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if a[0]==b[0] and a[1]<b[1]:
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antinodes.add((a[0],a[1]-dx))
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antinodes.add((b[0],b[1]+dx))
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if a[0]==b[0] and a[1]>b[1]:
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antinodes.add((a[0],a[1]+dx))
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antinodes.add((b[0],b[1]-dx))
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# positive slope
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if a[0]<b[0] and a[1]<b[1]:
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antinodes.add((a[0]-dy,a[1]-dx))
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antinodes.add((b[0]+dy,b[1]+dx))
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if a[0]>b[0] and a[1]>b[1]:
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antinodes.add((a[0]+dy,a[1]+dx))
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antinodes.add((b[0]-dy,b[1]-dx))
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# negative slope
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if a[0]<b[0] and a[1]>b[1]:
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antinodes.add((a[0]-dy,a[1]+dx))
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antinodes.add((b[0]+dy,b[1]-dx))
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if a[0]>b[0] and a[1]<b[1]:
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antinodes.add((a[0]+dy,a[1]-dx))
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antinodes.add((b[0]-dy,b[1]+dx))
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def boundscheck(antinode):
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if antinode[0] < 0: return False
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if antinode[0] >= ly: return False
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if antinode[1] < 0: return False
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if antinode[1] >= lx: return False
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return True
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def printmap():
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with open("day08") as f:
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for y,l in enumerate(f):
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for x,c in enumerate(l):
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if c == '.':
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if (y,x) in antinodes2:
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print("#", end=" ")
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else: print(".", end=" ")
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else:
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print(c.strip(), end=" ")
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print()
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res = len({antinode for antinode in antinodes if boundscheck(antinode)})
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# 2
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antinodes2 = set()
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for (_, coords) in freqmap.items():
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for s,a in enumerate(coords):
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for b in coords[s+1:]:
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slope = ((a[0]-b[0]) / (a[1]-b[1]))
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# y = mx + y0
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y0 = a[0] - slope*a[1]
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for x in range(lx):
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y = (slope*x)+y0
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if abs(round(y)-y) < 0.0001:
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antinodes2.add((int(round(y)), x))
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res2 = len({antinode for antinode in antinodes2 if boundscheck(antinode)})
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