day17: optimized part 1, merge into partboth.clj

master
Clyne 3 years ago
parent 98fe7cf73b
commit fced4abf72

@ -1,34 +0,0 @@
(def target-area [[169 -8] [206 -108]])
;(def target-area [[20 -5] [30 -10]])
(def initial-pos [0 0])
(defn beyond-target? [[[tbx tby] [tex tey]] [x y]]
(or (> x tex) (< y tey)))
(defn within-target? [[[tbx tby] [tex tey]] [x y]]
(and (>= x tbx) (<= x tex) (<= y tby) (>= y tey)))
(defn apply-velocity [[pos vel]]
[[(+ (first pos) (first vel)) (+ (second pos) (second vel))]
[(cond-> (first vel) (> (first vel) 0) dec (< (first vel) 0) inc) (dec (second vel))]])
(defn path-builder [vel] (iterate apply-velocity [initial-pos vel]))
(defn build-path [target vel]
(map first
(take-while (comp not (partial beyond-target? target) first)
(path-builder vel))))
(defn path-height [target vel]
(let [path (build-path target vel)]
(when (within-target? target (last path))
(apply max (map second path)))))
(def tnum-seq (iterate #(do [(+ (first %) (second %)) (inc (second %))]) [0 1]))
(let [x (second (last (take-while #(< (first %) (first (first target-area))) tnum-seq)))]
(println
(apply max
(filter some?
(for [y (range -2000 2000)] (path-height target-area [x y]))))))

@ -9,14 +9,12 @@
(and (>= x tbx) (<= x tex) (<= y tby) (>= y tey))) (and (>= x tbx) (<= x tex) (<= y tby) (>= y tey)))
(defn apply-velocity [[[px py] [vx vy]]] (defn apply-velocity [[[px py] [vx vy]]]
[[(+ px vx) (+ py vy)] [(if (pos? vx) (dec vx) 0) (dec vy)]]) [[(+ px vx) (+ py vy)] [(cond-> vx (pos? vx) dec) (dec vy)]])
(defn path-builder [vel] (iterate apply-velocity [initial-pos vel]))
(defn build-path [target vel] (defn build-path [target vel]
(->> (path-builder vel) (->> (iterate apply-velocity [initial-pos vel])
(take-while (comp not (partial beyond-target? target) first)) (take-while (comp not (partial beyond-target? target) first))
(map first))) (mapv first)))
(defn path-height [target vel] (defn path-height [target vel]
(let [path (build-path target vel)] (let [path (build-path target vel)]
@ -28,17 +26,12 @@
(let [[tb te] target-area (let [[tb te] target-area
lowest-x (second (last (take-while #(< (first %) (first tb)) tnum-seq))) lowest-x (second (last (take-while #(< (first %) (first tb)) tnum-seq)))
lowest-y (second te) highest-y (dec (Math/abs (second te)))]
valid-paths (filter (comp some? first)
(for [y (range lowest-y 2000)]
[(path-height target-area [lowest-x y]) y]))
highest-path (reduce #(if (> (first %1) (first %2)) %1 %2) valid-paths)]
(println (first highest-path))
(println (println
(path-height target-area [lowest-x highest-y])
(count (count
(filter (partial within-target? target-area) (filter (partial within-target? target-area)
(let [ys [(second te) (second highest-path)]] (for [x (range lowest-x (inc (first te)))
(for [x (range lowest-x (inc (first te))) y (range (second te) (inc highest-y))]
y (range (apply min ys) (inc (apply max ys)))] (last (build-path target-area [x y])))))))
(last (build-path target-area [x y]))))))))
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