84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
""" https://adventofcode.com/2019/day/12 """
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from itertools import combinations
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def readFile():
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with open(f"{__file__.rstrip('code.py')}input.txt", "r") as f:
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lines = [line[1:-2].replace(" ", "").split(",") for line in f.readlines()]
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return [(int(line[0][2:]), int(line[1][2:]), int(line[2][2:])) for line in lines]
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def cmp(a,b):
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return 0 if a == b else -1 if a < b else 1
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class Moon:
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def __init__(self, pos):
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self.pos = list(pos)
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self.vel = [0] * 3
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def changeGravity(self, other):
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for i in range(3):
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d = cmp(self.pos[i], other.pos[i])
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self.vel[i] -= d
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other.vel[i] += d
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def move(self):
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for i in range(3):
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self.pos[i] += self.vel[i]
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def energy(self):
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pot = sum([abs(p) for p in self.pos])
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kin = sum([abs(v) for v in self.vel])
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return pot, kin, pot * kin
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def simulate(moons : list, steps = 1):
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for i in range(steps):
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for m, n in list(combinations(moons, 2)):
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m.changeGravity(n)
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for moon in moons:
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moon.move()
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def lcm(x, y):
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tmp = x * y
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while y:
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x, y = y, x % y
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return tmp // x
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def part1(vals: list):
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moons = [Moon(val) for val in vals]
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simulate(moons, 1000)
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return sum([moon.energy()[2] for moon in moons])
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def part2(vals: list):
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dims = [0, 0, 0]
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for i in range(3):
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moons = [Moon(val) for val in vals]
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oPos = [moon.pos[i] for moon in moons]
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while 1:
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simulate(moons)
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dims[i] += 1
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if [moon.pos[i] for moon in moons] == oPos and \
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[moon.vel[i] for moon in moons] == [0, 0, 0, 0]:
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break
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return lcm(dims[0], lcm(dims[1], dims[2]))
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def test():
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moons = [Moon(p) for p in ((-1,0,2), (2,-10,-7), (4,-8,8), (3,5,-1))]
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simulate(moons, 10)
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assert sum([moon.energy()[2] for moon in moons]) == 179
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vpos, vvel = ([2,1,-3],[1,-8,0],[3,-6,1],[2,0,4]), ([-3,-2,1],[-1,1,3],[3,2,-3],[1,-1,-1])
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for i in range(4):
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assert vpos[i] == moons[i].pos and vvel[i] == moons[i].vel
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moons = [Moon(p) for p in ((-8,-10,0), (5,5,10), (2,-7,3), (9,-8,-3))]
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simulate(moons,100)
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assert sum([moon.energy()[2] for moon in moons]) == 1940
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assert part2(((-1,0,2),(2,-10,-7),(4,-8,8),(3,5,-1))) == 2772
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assert part2(((-8,-10,0),(5,5,10),(2,-7,3),(9,-8,-3))) == 4686774924
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if __name__ == "__main__":
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test()
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vals = readFile()
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print(f"Part 1: {part1(vals)}")
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print(f"Part 2: {part2(vals)}") |