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Exercism: Bird Watcher

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Julio Biason 3 years ago
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  1. 20
      clojure/bird-watcher/.exercism/config.json
  2. 1
      clojure/bird-watcher/.exercism/metadata.json
  3. 75
      clojure/bird-watcher/HELP.md
  4. 3
      clojure/bird-watcher/HINTS.md
  5. 121
      clojure/bird-watcher/README.md
  6. 6
      clojure/bird-watcher/deps.edn
  7. 4
      clojure/bird-watcher/project.clj
  8. 38
      clojure/bird-watcher/src/bird_watcher.clj
  9. 54
      clojure/bird-watcher/test/bird_watcher_test.clj

20
clojure/bird-watcher/.exercism/config.json

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{
"blurb": "Learn about vectors by counting the birds in your garden",
"authors": [
"porkostomus"
],
"forked_from": [
"csharp/bird-watcher"
],
"files": {
"solution": [
"src/bird_watcher.clj"
],
"test": [
"test/bird_watcher_test.clj"
],
"exemplar": [
".meta/exemplar.clj"
]
}
}

1
clojure/bird-watcher/.exercism/metadata.json

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{"track":"clojure","exercise":"bird-watcher","id":"596ec3f86dda4444960239175b452aa8","url":"https://exercism.org/tracks/clojure/exercises/bird-watcher","handle":"JBiason","is_requester":true,"auto_approve":false}

75
clojure/bird-watcher/HELP.md

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# Help
## Running the tests
## Clojure CLI
The Clojure exercises on Exercism ship with a `deps.edn` file with a `:test` alias to invoke the [cognitect-labs test-runner](https://github.com/cognitect-labs/test-runner):
``` bash
$ clj -X:test
```
## Leiningen
Leiningen can also be used to run the exercise's test by running the following command from the exercise's directory:
```bash
lein test
```
## REPL
To use the REPL to run the exercise's test, run the following command from the exercise's directory:
```bash
$ clj
```
-or-
```bash
$ lein repl
```
Then `require` the exercise's test namespace and the Clojure test namespace):
```clojure
;; replace <exercise> with the exercise's name
=> (require '<exercise>-test)
```
Then call `run-tests` on `<exercise>-test`:
```clojure
;; replace <exercise> with the exercise's name
=> (clojure.test/run-tests '<exercise>-test)
```
## Submitting your solution
You can submit your solution using the `exercism submit src/bird_watcher.clj` command.
This command will upload your solution to the Exercism website and print the solution page's URL.
It's possible to submit an incomplete solution which allows you to:
- See how others have completed the exercise
- Request help from a mentor
## Need to get help?
If you'd like help solving the exercise, check the following pages:
- The [Clojure track's documentation](https://exercism.org/docs/tracks/clojure)
- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
To get help if you're having trouble, you can use one of the following resources:
- [Ask Clojure](https://ask.clojure.org/) Official forum for Clojure Q & A.
- [ClojureDocs](https://clojuredocs.org) A repository of language references and examples by function or keyword.
- [/r/clojure](https://www.reddit.com/r/clojure) is the Clojure subreddit.
- [StackOverflow](http://stackoverflow.com/questions/tagged/clojure) can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.
- [Clojureverse](https://clojureverse.org/) Friendly and inclusive Clojure(Script) Community

3
clojure/bird-watcher/HINTS.md

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# Hints
<!-- TODO: add hints -->

121
clojure/bird-watcher/README.md

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# Bird Watcher
Welcome to Bird Watcher on Exercism's Clojure Track.
If you need help running the tests or submitting your code, check out `HELP.md`.
If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
## Introduction
A `vector` in Clojure is a sequential, indexed, immutable collection of zero or more values. This means that once a vector has been created, it cannot be modified. Functions for operating on vectors will return a new vector, while the original vector remains unchanged. The values in a vector may be of heterogenous types. Vectors can be defined as follows:
```clojure
(def empty [])
(def single-value 5)
(def single-value-alternative (vector 5))
(def three-values [a b c]
```
Elements can be retrieved from a vector using an index. Clojure vectors are zero-based, meaning that the first element's index is always zero:
```clojure
(def numbers [2 3 5])
;; Read value from vector
(get numbers 2)
;;=> 5
;; Update value in vector
(assoc numbers 2 9)
;;=> [2 3 9]
```
The original vector is unchanged:
```clojure
numbers
;;=> [2 3 5]
```
To remember the updated value, we need to pass it along or capture it in a var:
```clojure
(def updated-numbers
(assoc numbers 2 9))
(get updated-numbers 2)
;;=> 9
```
## Instructions
You're an avid bird watcher that keeps track of how many birds have visited your garden in the last seven days.
You have six tasks, all dealing with the numbers of birds that visited your garden.
## 1. Check what the counts were last week
For comparison purposes, you always keep a copy of last week's counts nearby, which were: 0, 2, 5, 3, 7, 8 and 4. Create a vector containing last week's counts:
```clojure
last-week
;;=> [0 2 5 3 7 8 4]
```
## 2. Check how many birds visited today
Implement the `today` function to return how many birds visited your garden today. The bird counts are ordered by day, with the first element being the count of the oldest day, and the last element being today's count.
```clojure
(def birds-per-day [2 5 0 7 4 1])
(today birds-per-day)
;;=> 1
```
## 3. Increment today's count
Implement the `inc-bird` function to increment today's count:
```clojure
(inc-bird birds-per-day)
;;=> [2 5 0 7 4 2]
```
## 4. Check if there was a day with no visiting birds
Implement the `day-without-birds?` predicate function that returns `true` if there was a day at which zero birds visited the garden; otherwise, return `false`:
```clojure
(day-without-birds? birds-per-day)
;;=> true
```
## 5. Calculate the number of visiting birds for the first number of days
Implement the `n-days-count` function that returns the number of birds that have visited your garden from the start of the week, but limit the count to the specified number of days from the start of the week.
```clojure
(n-days-count birds-per-day 4)
;;=> 14
```
## 6. Calculate the number of busy days
Some days are busier than others. A busy day is one where five or more birds have visited your garden.
Implement the `busy-days` function to return the number of busy days:
```clojure
(busy-days birds-per-day)
;;=> 2
```
## 7. Check for odd week
Over the last year, you've found that some weeks for the same, odd pattern, where the counts alternate between one and zero birds visiting. Implement the `odd-week?` function that returns `true` if the bird count pattern of this week matches the odd pattern:
```clojure
(odd-week? [1 0 1 0 1 0 1])
;;=> true
```
## Source
### Created by
- @porkostomus

6
clojure/bird-watcher/deps.edn

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{:aliases {:test {:extra-paths ["test"]
:extra-deps {io.github.cognitect-labs/test-runner
{:git/url "https://github.com/cognitect-labs/test-runner.git"
:sha "705ad25bbf0228b1c38d0244a36001c2987d7337"}}
:main-opts ["-m" "cognitect.test-runner"]
:exec-fn cognitect.test-runner.api/test}}}

4
clojure/bird-watcher/project.clj

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(defproject bird-watcher "0.1.0-SNAPSHOT"
:description "bird-watcher exercise."
:url "https://github.com/exercism/clojure/tree/main/exercises/concept/bird-watcher"
:dependencies [[org.clojure/clojure "1.10.0"]])

38
clojure/bird-watcher/src/bird_watcher.clj

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(ns bird-watcher)
(def last-week
[0 2 5 3 7 8 4]
)
(def birds-per-day
)
(defn today [birds]
(if (empty? (rest birds))
(first birds)
(today (rest birds)))
)
(defn inc-bird [birds]
(conj (pop birds) (+ (today birds) 1))
)
(defn day-without-birds? [birds]
(if (empty? birds)
false
(if (= (first birds) 0)
true
(day-without-birds? (rest birds))))
)
(defn n-days-count [birds n]
(reduce + (take n birds))
)
(defn busy-days [birds]
(count (filter #(> % 4) birds))
)
(defn odd-week? [birds]
(= birds [1 0 1 0 1 0 1])
)

54
clojure/bird-watcher/test/bird_watcher_test.clj

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(ns bird-watcher-test
(:require [clojure.test :refer [deftest testing is]]
bird-watcher))
(deftest last-week-test
(is (= [0 2 5 3 7 8 4] bird-watcher/last-week)))
(deftest today-disappointing-week-test
(testing "Today's bird count of disappointing week"
(is (= 0 (bird-watcher/today [0 0 2 0 0 1 0])))))
(deftest today-busy-week-test
(testing "Today's bird count of busy week"
(is (= 10 (bird-watcher/today [8 8 9 5 4 7 10])))))
(deftest increment-bird-no-visits-test
(testing "Increment today's count with no previous visits"
(is (= [6 5 5 11 2 5 1] (bird-watcher/inc-bird [6 5 5 11 2 5 0])))))
(deftest increment-bird-multiple-visits-test
(testing "Increment today's count with multiple previous visits"
(is (= [5 2 4 2 4 5 8] (bird-watcher/inc-bird [5 2 4 2 4 5 7])))))
(deftest day-without-birds-test
(testing "Has day without birds with day without birds"
(is (= true (bird-watcher/day-without-birds? [5 5 4 0 7 6 7])))))
(deftest no-day-without-birds-test
(testing "Has day without birds with no day without birds"
(is (= false (bird-watcher/day-without-birds? [5 5 4 1 7 6 7])))))
(deftest n-days-count-disappointing-week-test
(testing "Count for first three days of disappointing week"
(is (= 1 (bird-watcher/n-days-count [0, 0, 1, 0, 0, 1, 0] 3)))))
(deftest n-days-count-busy-week-test
(testing "Count for first 6 days of busy week"
(is (= 48 (bird-watcher/n-days-count [5, 9, 12, 6, 8, 8, 17] 6)))))
(deftest busy-days-disappointing-week-test
(testing "Busy days for disappointing week"
(is (= 0 (bird-watcher/busy-days [1 1 1 0 0 0 0])))))
(deftest busy-days-busy-week-test
(testing "Busy days for busy week"
(is (= 5 (bird-watcher/busy-days [4 9 5 7 8 8 2])))))
(deftest odd-week-matching-test
(testing "Odd week for week matching odd pattern"
(is (= true (bird-watcher/odd-week? [1 0 1 0 1 0 1])))))
(deftest odd-week-not-matching-test
(testing "Odd week for week that does not match pattern"
(is (= false (bird-watcher/odd-week? [2 2 1 0 1 1 1])))))
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