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@@ -0,0 +1,83 @@
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+from util import get_input
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+from itertools import product
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+from more_itertools import flatten
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+from math import sqrt, ceil, floor
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+
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+input = get_input("17.input")
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+
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+stuff = input[0].split()
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+
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+tx = [int(a) for a in stuff[2][2:-1].split("..")]
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+ty = [int(a) for a in stuff[3][2:].split("..")]
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+
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+def hits(velx, tx, ty):
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+ # High school math comes in handy once again...
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+
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+ #x = velx + velx - 1 + velx - 2 + velx - 3 = velx * steps - steps (steps - 1) / 2 = (velx + 1/2) * steps - steps^2 / 2
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+ # 2 x = (2 velx + 1) steps - steps^2
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+ # 2x - (2 velx + 1) steps + steps^2 = 0
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+
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+ try:
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+ minsteps = ceil((2 * velx + 1) / 2 - sqrt(pow((2 * velx + 1) / 2, 2) - 2 * tx[0]))
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+ except ValueError:
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+ # Equation has no solution;
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+ # projectile never reaches area
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+ return []
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+
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+ try:
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+ maxsteps = floor((2 * velx + 1) / 2 - sqrt(pow((2 * velx + 1) / 2, 2) - 2 * tx[1]))
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+ except ValueError:
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+ # Projectile x-velocity reaches 0
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+ # while above the target area
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+ maxsteps = minsteps + 1000
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+
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+ res = []
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+ for nstep in range(minsteps, maxsteps + 1):
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+ #y = vely * nstep - nstep * (nstep - 1) / 2
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+ #vely * nstep = nstep * (nstep - 1) / 2 + y
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+ #vely = (nstep * (nstep - 1) / 2 + y) / nstep
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+ minvely = ceil((nstep * (nstep - 1) / 2 + ty[0]) / nstep)
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+ maxvely = floor((nstep * (nstep - 1) / 2 + ty[1]) / nstep)
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+
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+ for vely in range(minvely, maxvely + 1):
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+ res.append((velx, vely))
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+ return list(set(res))
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+
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+
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+# This is slow garbage, leaving it here so you can laugh at me
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+def naive_hits(vel, tx, ty):
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+ topy = 0
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+ pos = (0, 0)
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+ startvel = vel
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+ while True:
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+ if pos[0] >= tx[0] and pos[0] <= tx[1]:
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+ if pos[1] >= ty[0] and pos[1] <= ty[1]:
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+ return (topy, startvel)
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+ if pos[1] < ty[0]:
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+ return (-1000, startvel)
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+ if pos[0] > tx[1]:
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+ return (-1000, startvel)
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+ if vel[0] == 0:
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+ dx = 0
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+ elif vel[0] < 0:
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+ dx = 1
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+ else:
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+ dx = -1
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+ pos = (pos[0] + vel[0], pos[1] + vel[1])
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+ vel = (vel[0] + dx, vel[1] - 1)
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+ topy = max(pos[1], topy)
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+
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+
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+hits = list(flatten([hits(x, tx, ty) for x in range(0, 70)]))
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+
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+# Find highest point on parabola using initial y-velocity
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+maxvely = max([h[1] for h in hits])
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+# D(vely * t - (t ^ 2) / 2) == 0
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+# vely - t == 0
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+t = maxvely
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+maxy = int(t * t - t * (t - 1) / 2)
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+
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+print("Part 1:", maxy)
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+
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+# This is easy now lol
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+print("Part 2:", len(hits))
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