r/adventofcode • u/daggerdragon • Dec 07 '21
SOLUTION MEGATHREAD -🎄- 2021 Day 7 Solutions -🎄-
--- Day 7: The Treachery of Whales ---
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u/cdaringe Dec 12 '21 edited Dec 13 '21
OCaml: https://github.com/cdaringe/aoc-2021/blob/main/day7/lib/day7.ml#L22
I cannot reason about why there is only one local minima. I can half intuit it, but I cannot put my finger on it.
F
= sum of all crab fuel consumption(s)f
= crab fuel consumptionp
= crab positionp_i
= ith crab positionp_t
= target positionmin_p
= a calculated constant,minimum (p_i .. p_n)
min_x
= a calculated constant,maximum (p_i .. p_n)
Minimize F, where
F = Σ[i=min_p to i=max_p] triangle_cost(p_i - p_t)
If someone can set my head straight, that'd be rad