aoc day7

Author: quan-nh

resources/2018/day07

@@ -0,0 +1,101 @@
+Step J must be finished before step H can begin.
+Step N must be finished before step C can begin.
+Step G must be finished before step P can begin.
+Step M must be finished before step I can begin.
+Step H must be finished before step X can begin.
+Step B must be finished before step Y can begin.
+Step C must be finished before step L can begin.
+Step F must be finished before step I can begin.
+Step V must be finished before step O can begin.
+Step W must be finished before step Q can begin.
+Step E must be finished before step L can begin.
+Step U must be finished before step S can begin.
+Step D must be finished before step K can begin.
+Step Y must be finished before step X can begin.
+Step T must be finished before step R can begin.
+Step I must be finished before step K can begin.
+Step A must be finished before step K can begin.
+Step L must be finished before step X can begin.
+Step Q must be finished before step S can begin.
+Step S must be finished before step O can begin.
+Step P must be finished before step Z can begin.
+Step X must be finished before step R can begin.
+Step Z must be finished before step O can begin.
+Step O must be finished before step K can begin.
+Step R must be finished before step K can begin.
+Step J must be finished before step W can begin.
+Step F must be finished before step V can begin.
+Step A must be finished before step X can begin.
+Step Z must be finished before step K can begin.
+Step M must be finished before step O can begin.
+Step X must be finished before step K can begin.
+Step E must be finished before step K can begin.
+Step J must be finished before step K can begin.
+Step E must be finished before step Y can begin.
+Step B must be finished before step Q can begin.
+Step X must be finished before step Z can begin.
+Step D must be finished before step L can begin.
+Step N must be finished before step I can begin.
+Step N must be finished before step B can begin.
+Step V must be finished before step A can begin.
+Step H must be finished before step R can begin.
+Step N must be finished before step L can begin.
+Step U must be finished before step O can begin.
+Step A must be finished before step O can begin.
+Step V must be finished before step Z can begin.
+Step O must be finished before step R can begin.
+Step Q must be finished before step P can begin.
+Step F must be finished before step Q can begin.
+Step P must be finished before step R can begin.
+Step S must be finished before step X can begin.
+Step J must be finished before step E can begin.
+Step V must be finished before step P can begin.
+Step M must be finished before step D can begin.
+Step I must be finished before step S can begin.
+Step Q must be finished before step O can begin.
+Step M must be finished before step H can begin.
+Step W must be finished before step X can begin.
+Step D must be finished before step O can begin.
+Step X must be finished before step O can begin.
+Step Y must be finished before step Z can begin.
+Step F must be finished before step L can begin.
+Step V must be finished before step T can begin.
+Step V must be finished before step E can begin.
+Step Y must be finished before step A can begin.
+Step I must be finished before step R can begin.
+Step L must be finished before step O can begin.
+Step U must be finished before step X can begin.
+Step Q must be finished before step X can begin.
+Step P must be finished before step X can begin.
+Step G must be finished before step C can begin.
+Step A must be finished before step L can begin.
+Step M must be finished before step U can begin.
+Step L must be finished before step S can begin.
+Step S must be finished before step P can begin.
+Step S must be finished before step K can begin.
+Step F must be finished before step T can begin.
+Step Q must be finished before step K can begin.
+Step G must be finished before step M can begin.
+Step G must be finished before step F can begin.
+Step T must be finished before step Q can begin.
+Step F must be finished before step Z can begin.
+Step I must be finished before step Z can begin.
+Step N must be finished before step X can begin.
+Step J must be finished before step F can begin.
+Step W must be finished before step E can begin.
+Step M must be finished before step Z can begin.
+Step G must be finished before step X can begin.
+Step V must be finished before step U can begin.
+Step P must be finished before step O can begin.
+Step U must be finished before step R can begin.
+Step G must be finished before step Z can begin.
+Step F must be finished before step R can begin.
+Step L must be finished before step R can begin.
+Step F must be finished before step A can begin.
+Step I must be finished before step O can begin.
+Step D must be finished before step T can begin.
+Step U must be finished before step L can begin.
+Step B must be finished before step S can begin.
+Step S must be finished before step Z can begin.
+Step J must be finished before step N can begin.
+Step H must be finished before step T can begin.

src/adventofcode2018/day07.janet

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+(def input (slurp "../../resources/2018/day07"))
+
+(def nodes @{})
+(def edges @{})
+
+# parse input
+(def instructions
+ ~{:letter (range "AZ")
+   :instruction (* "Step " ':letter " must be finished before step " ':letter " can begin.\n")
+   :main (some (cmt :instruction
+                    ,(fn [a b]
+                      (put nodes a true)
+                      (put nodes b true)
+                      (put edges [a b] true))))})
+
+(peg/match instructions input)
+
+
+(defn start-nodes
+  "nodes with no incoming edge"
+  [_nodes _edges]
+  (let [tmp-nodes (table ;(kvs _nodes))]
+    (loop [[_ a] :keys _edges]
+      (put tmp-nodes a nil))
+    (keys tmp-nodes)))
+  
+(defn neighbors [n _edges]
+  (->> (keys _edges)
+       (filter (fn [[a _]] (= a n)))
+       (map last)))
+  
+
+(defn no-incoming? [n _edges]
+  (empty? (filter (fn [[_ a]] (= a n)) (keys _edges))))
+
+(def q (start-nodes nodes edges))
+
+
+(def steps @[])
+(def tmp-edges (table ;(kvs edges)))
+
+(while (not (empty? q))
+  (let [n (array/pop (sort q order>))]
+    (array/push steps n)
+    (each m (neighbors n edges)
+      (put tmp-edges [n m] nil)
+      (if (no-incoming? m tmp-edges) (array/push q m)))))
+
+(pp (string/join steps)) # GJFMDHNBCIVTUWEQYALSPXZORK