exercises(high-scores): implement

config.json

@@ -35,6 +35,24 @@
   "exercises": {
     "concept": [],
     "practice": [
+      {
+        "uuid": "fafe82fb-a54a-40d3-b082-4429e080e435",
+        "slug": "high-scores",
+        "name": "High scores",
+        "practices": [
+          "integers",
+          "slices",
+          "sorting",
+          "structs"
+        ],
+        "prerequisites": [
+          "integers",
+          "slices",
+          "sorting",
+          "structs"
+        ],
+        "difficulty": 1
+      },
       {
         "uuid": "25a0331e-612f-48c1-8a3f-9b0e9601a2fa",
         "slug": "hello-world",

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": [
+    "ee7"
+  ],
+  "files": {
+    "solution": [
+      "high_scores.zig"
+    ],
+    "test": [
+      "test_high_scores.zig"
+    ],
+    "example": [
+      ".meta/example.zig"
+    ]
+  },
+  "blurb": "Manage a player's High Score list.",
+  "source": "Tribute to the eighties' arcade game Frogger"
+}

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

@@ -0,0 +1,28 @@
+const std = @import("std");
+
+pub const HighScores = struct {
+    scores: []const u32,
+
+    /// Asserts `scores.len > 0`.
+    pub fn init(scores: []const u32) HighScores {
+        std.debug.assert(scores.len > 0);
+        return .{ .scores = scores };
+    }
+
+    pub fn latest(self: HighScores) u32 {
+        return self.scores[self.scores.len - 1];
+    }
+
+    pub fn personalBest(self: HighScores) u32 {
+        return std.mem.max(u32, self.scores);
+    }
+
+    /// Writes (at most) the three highest scores from `self` into `buffer`.
+    /// Asserts `buffer.len == self.scores.len`.
+    pub fn personalTopThree(self: HighScores, buffer: []u32) []u32 {
+        std.debug.assert(buffer.len == self.scores.len);
+        std.mem.copy(u32, buffer, self.scores);
+        std.mem.sort(u32, buffer, {}, std.sort.desc(u32));
+        return buffer[0..@min(buffer.len, 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.zig

@@ -0,0 +1,27 @@
+pub const HighScores = struct {
+    // Please implement the field(s) of this struct.
+    foo: void,
+
+    /// Asserts `scores.len > 0`.
+    pub fn init(scores: []const u32) HighScores {
+        _ = scores;
+        @compileError("please implement the init method");
+    }
+
+    pub fn latest(self: HighScores) u32 {
+        _ = self;
+        @compileError("please implement the latest method");
+    }
+
+    pub fn personalBest(self: HighScores) u32 {
+        _ = self;
+        @compileError("please implement the personalBest method");
+    }
+
+    /// Writes (at most) the three highest scores from `self` into `buffer`.
+    pub fn personalTopThree(self: HighScores, buffer: []u32) []u32 {
+        _ = self;
+        _ = buffer;
+        @compileError("please implement the personalTopThree method");
+    }
+};

exercises/practice/high-scores/test_high_scores.zig

@@ -0,0 +1,112 @@
+const std = @import("std");
+const testing = std.testing;
+
+const high_scores = @import("high_scores.zig");
+const HighScores = high_scores.HighScores;
+
+test "list of scores" {
+    const expected = [_]u32{ 30, 50, 20, 70 };
+    const scores = [_]u32{ 30, 50, 20, 70 };
+    const h = HighScores.init(&scores);
+    const actual = h.scores;
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "latest score" {
+    const expected: u32 = 30;
+    const scores = [_]u32{ 100, 0, 90, 30 };
+    const h = HighScores.init(&scores);
+    const actual = h.latest();
+    try testing.expectEqual(expected, actual);
+}
+
+test "personal best" {
+    const expected: u32 = 100;
+    const scores = [_]u32{ 40, 100, 70 };
+    const h = HighScores.init(&scores);
+    const actual = h.personalBest();
+    try testing.expectEqual(expected, actual);
+}
+
+test "personal top three from a list of scores" {
+    const expected = [_]u32{ 100, 90, 70 };
+    const scores = [_]u32{ 10, 30, 90, 30, 100, 20, 10, 0, 30, 40, 40, 70, 70 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    const actual = h.personalTopThree(&buffer);
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "personal top highest to lowest" {
+    const expected = [_]u32{ 30, 20, 10 };
+    const scores = [_]u32{ 20, 10, 30 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    const actual = h.personalTopThree(&buffer);
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "personal top when there is a tie" {
+    const expected = [_]u32{ 40, 40, 30 };
+    const scores = [_]u32{ 40, 20, 40, 30 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    const actual = h.personalTopThree(&buffer);
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "personal top when there are less than 3" {
+    const expected = [_]u32{ 70, 30 };
+    const scores = [_]u32{ 30, 70 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    const actual = h.personalTopThree(&buffer);
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "personal top when there is only one" {
+    const expected = [_]u32{40};
+    const scores = [_]u32{40};
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    const actual = h.personalTopThree(&buffer);
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "latest score after personal top scores" {
+    const expected: u32 = 30;
+    const scores = [_]u32{ 70, 50, 20, 30 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    _ = h.personalTopThree(&buffer);
+    const actual = h.latest();
+    try testing.expectEqual(expected, actual);
+}
+
+test "scores after personal top scores" {
+    const expected = [_]u32{ 30, 50, 20, 70 };
+    const scores = [_]u32{ 30, 50, 20, 70 };
+    const h = HighScores.init(&scores);
+    var buffer: [scores.len]u32 = undefined;
+    _ = h.personalTopThree(&buffer);
+    const actual = h.scores;
+    try testing.expectEqualSlices(u32, &expected, actual);
+}
+
+test "latest score after personal best" {
+    const expected: u32 = 30;
+    const scores = [_]u32{ 20, 70, 15, 25, 30 };
+    const h = HighScores.init(&scores);
+    _ = h.personalBest();
+    const actual = h.latest();
+    try testing.expectEqual(expected, actual);
+}
+
+test "scores after personal best" {
+    const expected = [_]u32{ 20, 70, 15, 25, 30 };
+    const scores = [_]u32{ 20, 70, 15, 25, 30 };
+    const h = HighScores.init(&scores);
+    _ = h.personalBest();
+    const actual = h.scores;
+    try testing.expectEqualSlices(u32, &expected, actual);
+}