Crime at Piccadilly Circus

clojure-dojo.md

Results of the Clojure Dojo

This gist is just a placeholder for your solution of the Clojure Dojo from the Amsterdam Clojurians meetup.

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first.clj

(ns meetup.first
  (:require [clojure.string :refer [split split-lines]]))

; input-first.txt looks like this:
; 5 10
; 4
; 1 8
; 5 8
; 7 10
; 8 9
;
; timeline
; ========================
; 1 2 3 4 | 5 6 7 8      |
;         | 5 6 7 8      |
;         |     7 8 9 10 |
;         |       8 9    |

(defn parse-line
  [line]
  (map read-string (split line #" ")))

(defn parse-input
  [input]
  (let [parsed-lines (map parse-line (split-lines input))
        [[start end] _ & humans-start-end] parsed-lines]
    {:start start :end end :humans-start-end humans-start-end}))

(defn mask-ranges
  [mask & ranges]
  (let [mask-min (first mask)
        mask-max (last mask)]
    (map
      (fn [r] (range (max (first r) mask-min) (min (last r) mask-max)))
      ranges)))

(defn min-max
  [numbers]
  [(apply min numbers) (apply max numbers)])

(defn min-max-human-in-time-range
  [{:keys [start end humans-start-end]}]
  (let [human-ranges (apply mask-ranges
                            [start (inc end)]
                            (map (fn [[start end]] [start (inc end)]) humans-start-end))]
    (->> human-ranges
         flatten
         frequencies
         vals
         min-max)))

(println
  (min-max-human-in-time-range
    (parse-input (slurp "./resources/input-first.txt"))))

first.rb

class First
  def initialize(input)
    lines = input.split($/).map { |l| l.split(' ').map(&:to_i) }
    start_end, _, *@human_ranges = lines
    @start, @end = start_end
  end

  def solve
    @human_ranges
      .flat_map { |(arrive, leave)| (([@start, arrive].max)..([@end, leave].min)).to_a }
      .each_with_object(Hash.new(0)) { |time_frame, obj| obj[time_frame] += 1 }
      .values
      .minmax
  end
end

p First.new(File.read('./resources/input-first.txt')).solve