From e6afd7fe60a24d4dcffffae42ececc15e021a3f5 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Thu, 9 Dec 2021 17:37:13 -0500
Subject: day9: improved both parts
---
day9/part1.clj | 40 ++++++++++++----------------------------
day9/part2.clj | 45 ++++++++++++++++++---------------------------
2 files changed, 30 insertions(+), 55 deletions(-)
diff --git a/day9/part1.clj b/day9/part1.clj
index 813d5a6..7bd8e23 100644
--- a/day9/part1.clj
+++ b/day9/part1.clj
@@ -5,33 +5,17 @@
(mapv (partial mapv #(- (int %) 48)))
))
-(defn compare-heights [a b]
- (if (or (nil? a) (nil? b) (< a b)) 1 0))
+(defn get-adj [y x]
+ (map (partial get-in input-map)
+ [[(dec y) x] [(inc y) x] [y (dec x)] [y (inc x)]]))
-(println
- (apply +
- (for [y (range 0 (count input-map))
- x (range 0 (count (first input-map)))]
- (let [height (get-in input-map [y x])]
- (if
- (= 4
- (apply +
- (map
- (partial compare-heights height)
- [
- (get-in input-map [(dec y) x])
- (get-in input-map [(inc y) x])
- (get-in input-map [y (dec x)])
- (get-in input-map [y (inc x)])
- ]
- )
- )
- )
- (inc height)
- 0
- )
- )
- )
- )
- )
+(->> (for [y (range 0 (count input-map))
+ x (range 0 (count (first input-map)))
+ :let [height (get-in input-map [y x])]
+ :when (every? #(or (nil? %) (< height %))
+ (get-adj y x))]
+ (inc height))
+ (apply +)
+ (println)
+ )
diff --git a/day9/part2.clj b/day9/part2.clj
index dd05b7d..3030c4e 100644
--- a/day9/part2.clj
+++ b/day9/part2.clj
@@ -1,9 +1,4 @@
-(def input-map
- (->> (slurp "./in")
- (clojure.string/split-lines)
- (mapv vec)
- (mapv (partial mapv #(- (int %) 48)))
- ))
+(require '[clojure.set])
(defn get-adj
"Gets vector of coords surrounding (x, y)."
@@ -11,18 +6,16 @@
(defn basin-continues?
"Determines if `b` is a continuation of the basin that includes `a`."
- [a b]
- (and (some? b) (not= b 9) (> b a)))
+ [a b] (and (some? b) (not= b 9) (> b a)))
(defn basin-bottom?
"Determines if point `p` in `hmap` is the bottom of a basin surrounded by
points `adj`."
[hmap p adj]
- (empty?
- (filter
- #(let [q (get-in hmap %)] (and (some? q) (> (get-in hmap p) q)))
- adj
- )))
+ (every?
+ #(let [q (get-in hmap %)] (or (nil? q) (< (get-in hmap p) q)))
+ adj
+ ))
(defn find-basin
"If point `yx` in `hmap` is in a basin (determined using `adj`), return a
@@ -31,21 +24,19 @@
(let [res (filter #(basin-continues? (get-in hmap yx)
(get-in hmap %))
adj)]
- (if-not (empty? res)
- (apply
- (partial concat res)
- (map
- #(find-basin hmap % (apply get-adj %))
- res
- )))))
-
-(->> (for [y (range 0 (count input-map))
- x (range 0 (count (first input-map)))]
- (let [adj (get-adj y x)]
- (when (basin-bottom? input-map [y x] adj)
- (inc (count (distinct (find-basin input-map [y x] adj))))
+ (apply (partial clojure.set/union res)
+ (map #(set (find-basin hmap % (apply get-adj %))) res)
)))
- (filter some?)
+
+(->> (slurp "./in")
+ (clojure.string/split-lines)
+ (mapv vec)
+ (mapv (partial mapv #(- (int %) 48)))
+ (#(for [y (range 0 (count %))
+ x (range 0 (count (first %)))
+ :let [adj (get-adj y x)]
+ :when (basin-bottom? % [y x] adj)]
+ (inc (count (find-basin % [y x] adj)))))
(sort >)
(take 3)
(apply *)
--
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