107 lines
2.5 KiB
Python
107 lines
2.5 KiB
Python
import itertools
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import math
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def get_circuit(a,circuits):
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if len(circuits) == 0:
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return None
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for circ in circuits:
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for pos in circ:
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if pos == a:
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return circ
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return None
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def add_circuit(a,b,circuits):
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circ_a = get_circuit(a,circuits)
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circ_b = get_circuit(b,circuits)
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if circ_a is None and circ_b is None:
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circuits.append([a,b])
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return True
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if circ_a is None and not circ_b is None:
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circ_b.append(a)
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return True
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if not circ_a is None and circ_b is None:
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circ_a.append(b)
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return True
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if not circ_a is None and not circ_b is None:
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if circ_a == circ_b:
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# Already part of same circuit
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return True
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else:
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# Merge circuits...
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# Copy a to b
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for circ in circ_a:
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circ_b.append(circ)
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# Empty a
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for _ in range(0, len(circ_a)):
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circ_a.pop()
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return True
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def get_lowest_distance(junctions_distance):
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a,b,_ = junctions_distance.pop()
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return a,b
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def distance(a,b):
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# https://en.wikipedia.org/wiki/Euclidean_distance
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return math.sqrt( pow((a[0]-b[0]),2) + pow((a[1]-b[1]),2) + pow((a[2]-b[2]),2) )
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def read_input(filename):
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space = []
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for line in open(filename).read().splitlines():
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x,y,z = line.split(",")
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space.append((int(x), int(y), int(z)))
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return space
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filename = "day08/example_input" # 40
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max_connections = 10
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filename = "day08/input" # 115885
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max_connections = 1000
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junctions = read_input(filename)
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# build list of (unique) combinations
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junctions_comb = itertools.combinations(junctions,2)
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print("Calculate distances")
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# Add distance to the list
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junctions_distance = []
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for a,b in junctions_comb:
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dist = distance(a,b)
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junctions_distance.append((a,b,dist))
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# Sort distance list, reversed so "pop()" will get/remove the shortest distance
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def jd_sort(junc_dist):
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return junc_dist[2]
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junctions_distance.sort(key=jd_sort, reverse=True)
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circuits = []
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connections = 0
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print("Make connections")
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while True:
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a,b = get_lowest_distance(junctions_distance)
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if add_circuit(a,b,circuits):
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connections += 1
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if connections == max_connections:
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break
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if connections % 100 == 0:
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print(f"Connections: {connections}")
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sizes = [len(i) for i in circuits]
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sizes.sort(reverse=True)
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print(f"3 largest circuits multiplied: {sizes[0]*sizes[1]*sizes[2]}")
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