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4d47's solution

to Series in the Clojure Track

Published at Jul 13 2018 · 0 comments
Test suite

Given a string of digits, output all the contiguous substrings of length n in that string in the order that they appear.

For example, the string "49142" has the following 3-digit series:

  • "491"
  • "914"
  • "142"

And the following 4-digit series:

  • "4914"
  • "9142"

And if you ask for a 6-digit series from a 5-digit string, you deserve whatever you get.

Note that these series are only required to occupy adjacent positions in the input; the digits need not be numerically consecutive.


A subset of the Problem 8 at Project Euler http://projecteuler.net/problem=8

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


(ns series-test
  (:require [clojure.test :refer [deftest is testing]]
            [series :refer [slices]]))

(deftest empty-string
  (testing "empty string with any number"
    (is (= [] (slices "" 1)))))

(deftest number-eq-zero
  (testing "number = 0"
    (is (= [""] (slices "123" 0)))))

(deftest number>string
  (testing "number > string-length"
    (is (= [] (slices "123" 1000)))))

(deftest number=string
  (testing "number = string-length"
    (is (= ["123"] (slices "123" 3)))))

(deftest number<string
  (testing "number < string-length"
    (is (= #{"123" "234" "345"} (set (slices "12345" 3))))))
(ns series
  (:require [clojure.string :refer [join]]))

(defn slices [s len]
  (if (zero? len)
    (map join (partition len 1 s))))

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