Add high-scores exercise

config.json

@@ -268,6 +268,14 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "high-scores",
+        "name": "High Scores",
+        "uuid": "0d19dee3-f4a8-4035-a436-388b71364202",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "list-ops",
         "name": "List Ops",

exercises/practice/high-scores/.docs/instructions.md

@@ -0,0 +1,6 @@
+# Instructions
+
+Manage a game player's High Score list.
+
+Your task is to build a high-score component of the classic Frogger game, one of the highest selling and most addictive games of all time, and a classic of the arcade era.
+Your task is to write methods that return the highest score from the list, the last added score and the three highest scores.

exercises/practice/high-scores/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "high-scores.rkt"
+    ],
+    "test": [
+      "high-scores-test.rkt"
+    ],
+    "example": [
+      ".meta/example.rkt"
+    ]
+  },
+  "blurb": "Manage a player's High Score list.",
+  "source": "Tribute to the eighties' arcade game Frogger"
+}

exercises/practice/high-scores/.meta/example.rkt

@@ -0,0 +1,17 @@
+#lang racket
+
+(provide high-scores%)
+
+(define high-scores%
+  (class object%
+    (init values)
+    (define current-values values)
+    (super-new)
+    (define/public (scores) current-values)
+    (define/public (latest) (car (reverse (scores))))
+    (define/public (personal-best) (apply max (scores)))
+    (define/public (personal-top-three)
+      (define sorted (sort (scores) >))
+      (if (< (length sorted) 3)
+          sorted
+          (take sorted 3)))))

exercises/practice/high-scores/.meta/tests.toml

@@ -0,0 +1,46 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[1035eb93-2208-4c22-bab8-fef06769a73c]
+description = "List of scores"
+
+[6aa5dbf5-78fa-4375-b22c-ffaa989732d2]
+description = "Latest score"
+
+[b661a2e1-aebf-4f50-9139-0fb817dd12c6]
+description = "Personal best"
+
+[3d996a97-c81c-4642-9afc-80b80dc14015]
+description = "Top 3 scores -> Personal top three from a list of scores"
+
+[1084ecb5-3eb4-46fe-a816-e40331a4e83a]
+description = "Top 3 scores -> Personal top highest to lowest"
+
+[e6465b6b-5a11-4936-bfe3-35241c4f4f16]
+description = "Top 3 scores -> Personal top when there is a tie"
+
+[f73b02af-c8fd-41c9-91b9-c86eaa86bce2]
+description = "Top 3 scores -> Personal top when there are less than 3"
+
+[16608eae-f60f-4a88-800e-aabce5df2865]
+description = "Top 3 scores -> Personal top when there is only one"
+
+[2df075f9-fec9-4756-8f40-98c52a11504f]
+description = "Top 3 scores -> Latest score after personal top scores"
+
+[809c4058-7eb1-4206-b01e-79238b9b71bc]
+description = "Top 3 scores -> Scores after personal top scores"
+
+[ddb0efc0-9a86-4f82-bc30-21ae0bdc6418]
+description = "Top 3 scores -> Latest score after personal best"
+
+[6a0fd2d1-4cc4-46b9-a5bb-2fb667ca2364]
+description = "Top 3 scores -> Scores after personal best"

exercises/practice/high-scores/high-scores-test.rkt

@@ -0,0 +1,88 @@
+#lang racket
+
+(require "high-scores.rkt")
+
+(module+ test
+  (require rackunit rackunit/text-ui)
+
+  (define suite
+    (test-suite
+     "high score tests"
+
+     (test-equal? "List of scores"
+                  (let* ([values '(30 50 20 70)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores scores))
+                  '(30 50 20 70))
+
+     (test-equal? "Latest scores"
+                  (let* ([values '(100 0 90 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores latest))
+                  30)
+
+     (test-equal? "Personal-best scores"
+                  (let* ([values '(40 100 70)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-best))
+                  100)
+
+     (test-equal? "Top 3 scores -> Personal top three from a list of scores"
+                  (let* ([values '(10 30 90 30 100 20 10 0 30 40 40 70 70)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-top-three))
+                  '(100 90 70))
+
+     (test-equal? "Top 3 scores -> Personal top highest to lowest"
+                  (let* ([values '(20 10 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-top-three))
+                  '(30 20 10))
+
+     (test-equal? "Top 3 scores -> Personal top when there is a tie"
+                  (let* ([values '(40 20 40 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-top-three))
+                  '(40 40 30))
+
+     (test-equal? "Top 3 scores -> Personal top when there are less than 3"
+                  (let* ([values '(30 70)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-top-three))
+                  '(70 30))
+
+     (test-equal? "Top 3 scores -> Personal top when there is only one"
+                  (let* ([values '(40)]
+                         [high-scores (new high-scores% [values values])])
+                    (send high-scores personal-top-three))
+                  '(40))
+
+     (test-equal? "Top 3 scores -> Latest score after personal top scores"
+                  (let* ([values '(70 50 20 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (and (send high-scores personal-top-three)
+                         (send high-scores latest)))
+                  30)
+
+     (test-equal? "Top 3 scores -> Scores after personal top scores"
+                  (let* ([values '(30 50 20 70)]
+                         [high-scores (new high-scores% [values values])])
+                    (and (send high-scores personal-top-three)
+                         (send high-scores scores)))
+                  '(30 50 20 70))
+
+     (test-equal? "Top 3 scores -> Latest score after personal best"
+                  (let* ([values '(20 70 15 25 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (and (send high-scores personal-best)
+                         (send high-scores latest)))
+                  30)
+
+     (test-equal? "Top 3 scores -> Scores after personal best"
+                  (let* ([values '(20 70 15 25 30)]
+                         [high-scores (new high-scores% [values values])])
+                    (and (send high-scores personal-best)
+                         (send high-scores scores)))
+                  '(20 70 15 25 30))))
+
+  (run-tests suite))

exercises/practice/high-scores/high-scores.rkt

@@ -0,0 +1,8 @@
+#lang racket
+
+(provide high-scores%)
+
+(define high-scores%
+  (class object%
+    ; implement me!
+    (super-new)))