Add split-second-stopwatch exercise #2968

config.json

@@ -842,6 +842,17 @@
         ],
         "difficulty": 4
       },
+      {
+        "slug": "split-second-stopwatch",
+        "name": "Split-Second Stopwatch",
+        "uuid": "9510c0ae-9977-4260-8991-0e8e849094b0",
+        "practices": [],
+        "prerequisites": [
+          "exceptions",
+          "if-else-statements"
+        ],
+        "difficulty": 4
+      },
       {
         "slug": "sum-of-multiples",
         "name": "Sum of Multiples",

exercises/practice/split-second-stopwatch/.docs/instructions.md

@@ -0,0 +1,22 @@
+# Instructions
+
+Your task is to build a stopwatch to keep precise track of lap times.
+
+The stopwatch uses four commands (start, stop, lap, and reset) to keep track of:
+
+1. The current lap's tracked time
+2. Previously recorded lap times
+
+What commands can be used depends on which state the stopwatch is in:
+
+1. Ready: initial state
+2. Running: tracking time
+3. Stopped: not tracking time
+
+| Command | Begin state | End state | Effect                                                   |
+| ------- | ----------- | --------- | -------------------------------------------------------- |
+| Start   | Ready       | Running   | Start tracking time                                      |
+| Start   | Stopped     | Running   | Resume tracking time                                     |
+| Stop    | Running     | Stopped   | Stop tracking time                                       |
+| Lap     | Running     | Running   | Add current lap to previous laps, then reset current lap |
+| Reset   | Stopped     | Ready     | Reset current lap and clear previous laps                |

exercises/practice/split-second-stopwatch/.docs/introduction.md

@@ -0,0 +1,6 @@
+# Introduction
+
+You've always run for the thrill of it — no schedules, no timers, just the sound of your feet on the pavement.
+But now that you've joined a competitive running crew, things are getting serious.
+Training sessions are timed to the second, and every split second counts.
+To keep pace, you've picked up the _Split-Second Stopwatch_ — a sleek, high-tech gadget that's about to become your new best friend.

exercises/practice/split-second-stopwatch/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "EmmanuelBerkowicz"
+  ],
+  "files": {
+    "solution": [
+      "src/main/java/SplitSecondStopwatch.java"
+    ],
+    "test": [
+      "src/test/java/SplitSecondStopwatchTest.java"
+    ],
+    "example": [
+      ".meta/src/reference/java/SplitSecondStopwatch.java"
+    ]
+  },
+  "blurb": "Keep track of time through a digital stopwatch.",
+  "source": "Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2547"
+}

exercises/practice/split-second-stopwatch/.meta/src/reference/java/SplitSecondStopwatch.java

@@ -0,0 +1,125 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class SplitSecondStopwatch {
+
+    /**
+     * A split-second stopwatch that tracks elapsed time with lap functionality.
+     * Supports start, stop, reset, and lap operations with precise time tracking.
+     * Times are formatted in HH:MM:SS format with two-digit precision.
+     *
+     * @see <a href="https://github.com/exercism/problem-specifications/tree/main/exercises/split-second-stopwatch">
+     * Problem Specifications
+     * </a>
+     */
+
+    private enum State { READY, RUNNING, STOPPED }
+
+    private State state;
+    private long totalCompletedLaps;  // Total time from completed laps
+    private long currentLapStart;     // When current lap started
+    private long accumulated;         // Accumulated time for current lap when stopped
+    private List<String> previousLaps;
+    private long mockTime;
+
+    public SplitSecondStopwatch() {
+        this.state = State.READY;
+        this.totalCompletedLaps = 0;
+        this.currentLapStart = 0;
+        this.accumulated = 0;
+        this.previousLaps = new ArrayList<>();
+        this.mockTime = 0;
+    }
+
+    public void start() {
+        if (state == State.RUNNING) {
+            throw new IllegalStateException("cannot start an already running stopwatch");
+        }
+
+        currentLapStart = mockTime;
+        state = State.RUNNING;
+    }
+
+    public void stop() {
+        if (state != State.RUNNING) {
+            throw new IllegalStateException("cannot stop a stopwatch that is not running");
+        }
+
+        accumulated += mockTime - currentLapStart;
+        state = State.STOPPED;
+    }
+
+    public void reset() {
+        if (state != State.STOPPED) {
+            throw new IllegalStateException("cannot reset a stopwatch that is not stopped");
+        }
+
+        state = State.READY;
+        totalCompletedLaps = 0;
+        currentLapStart = 0;
+        accumulated = 0;
+        previousLaps.clear();
+    }
+
+    public void lap() {
+        if (state != State.RUNNING) {
+            throw new IllegalStateException("cannot lap a stopwatch that is not running");
+        }
+
+        long currentLapTime = getCurrentLapTime();
+        totalCompletedLaps += currentLapTime;
+        previousLaps.add(formatTime(currentLapTime));
+
+        // Reset current lap and restart
+        accumulated = 0;
+        currentLapStart = mockTime;
+    }
+
+    public String state() {
+        return state.name().toLowerCase();
+    }
+
+    public String currentLap() {
+        return formatTime(getCurrentLapTime());
+    }
+
+    public String total() {
+        return formatTime(totalCompletedLaps + getCurrentLapTime());
+    }
+
+    public List<String> previousLaps() {
+        return new ArrayList<>(previousLaps);
+    }
+
+    public void advanceTime(String timeString) {
+        String[] parts = timeString.split(":");
+        long hours = Long.parseLong(parts[0]);
+        long minutes = Long.parseLong(parts[1]);
+        long seconds = Long.parseLong(parts[2]);
+
+        long milliseconds = (hours * 3600 + minutes * 60 + seconds) * 1000;
+        mockTime += milliseconds;
+    }
+
+    private long getCurrentLapTime() {
+        switch (state) {
+            case READY:
+                return 0;
+            case RUNNING:
+                return accumulated + (mockTime - currentLapStart);
+            case STOPPED:
+                return accumulated;
+            default:
+                throw new IllegalStateException("Invalid state");
+        }
+    }
+
+    private String formatTime(long milliseconds) {
+        long totalSeconds = milliseconds / 1000;
+        long hours = totalSeconds / 3600;
+        long minutes = (totalSeconds % 3600) / 60;
+        long seconds = totalSeconds % 60;
+
+        return String.format("%02d:%02d:%02d", hours, minutes, seconds);
+    }
+}

exercises/practice/split-second-stopwatch/.meta/tests.toml

@@ -0,0 +1,97 @@
+# 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.
+
+[ddb238ea-99d4-4eaa-a81d-3c917a525a23]
+description = "new stopwatch starts in ready state"
+
+[b19635d4-08ad-4ac3-b87f-aca10e844071]
+description = "new stopwatch's current lap has no elapsed time"
+
+[492eb532-268d-43ea-8a19-2a032067d335]
+description = "new stopwatch's total has no elapsed time"
+
+[8a892c1e-9ef7-4690-894e-e155a1fe4484]
+description = "new stopwatch does not have previous laps"
+
+[5b2705b6-a584-4042-ba3a-4ab8d0ab0281]
+description = "start from ready state changes state to running"
+
+[748235ce-1109-440b-9898-0a431ea179b6]
+description = "start does not change previous laps"
+
+[491487b1-593d-423e-a075-aa78d449ff1f]
+description = "start initiates time tracking for current lap"
+
+[a0a7ba2c-8db6-412c-b1b6-cb890e9b72ed]
+description = "start initiates time tracking for total"
+
+[7f558a17-ef6d-4a5b-803a-f313af7c41d3]
+description = "start cannot be called from running state"
+
+[32466eef-b2be-4d60-a927-e24fce52dab9]
+description = "stop from running state changes state to stopped"
+
+[621eac4c-8f43-4d99-919c-4cad776d93df]
+description = "stop pauses time tracking for current lap"
+
+[465bcc82-7643-41f2-97ff-5e817cef8db4]
+description = "stop pauses time tracking for total"
+
+[b1ba7454-d627-41ee-a078-891b2ed266fc]
+description = "stop cannot be called from ready state"
+
+[5c041078-0898-44dc-9d5b-8ebb5352626c]
+description = "stop cannot be called from stopped state"
+
+[3f32171d-8fbf-46b6-bc2b-0810e1ec53b7]
+description = "start from stopped state changes state to running"
+
+[626997cb-78d5-4fe8-b501-29fdef804799]
+description = "start from stopped state resumes time tracking for current lap"
+
+[58487c53-ab26-471c-a171-807ef6363319]
+description = "start from stopped state resumes time tracking for total"
+
+[091966e3-ed25-4397-908b-8bb0330118f8]
+description = "lap adds current lap to previous laps"
+
+[1aa4c5ee-a7d5-4d59-9679-419deef3c88f]
+description = "lap resets current lap and resumes time tracking"
+
+[4b46b92e-1b3f-46f6-97d2-0082caf56e80]
+description = "lap continues time tracking for total"
+
+[ea75d36e-63eb-4f34-97ce-8c70e620bdba]
+description = "lap cannot be called from ready state"
+
+[63731154-a23a-412d-a13f-c562f208eb1e]
+description = "lap cannot be called from stopped state"
+
+[e585ee15-3b3f-4785-976b-dd96e7cc978b]
+description = "stop does not change previous laps"
+
+[fc3645e2-86cf-4d11-97c6-489f031103f6]
+description = "reset from stopped state changes state to ready"
+
+[20fbfbf7-68ad-4310-975a-f5f132886c4e]
+description = "reset resets current lap"
+
+[00a8f7bb-dd5c-43e5-8705-3ef124007662]
+description = "reset clears previous laps"
+
+[76cea936-6214-4e95-b6d1-4d4edcf90499]
+description = "reset cannot be called from ready state"
+
+[ba4d8e69-f200-4721-b59e-90d8cf615153]
+description = "reset cannot be called from running state"
+
+[0b01751a-cb57-493f-bb86-409de6e84306]
+description = "supports very long laps"

exercises/practice/split-second-stopwatch/build.gradle

@@ -0,0 +1,25 @@
+plugins {
+    id "java"
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation platform("org.junit:junit-bom:5.10.0")
+    testImplementation "org.junit.jupiter:junit-jupiter"
+    testImplementation "org.assertj:assertj-core:3.25.1"
+
+    testRuntimeOnly "org.junit.platform:junit-platform-launcher"
+}
+
+test {
+    useJUnitPlatform()
+
+    testLogging {
+        exceptionFormat = "full"
+        showStandardStreams = true
+        events = ["passed", "failed", "skipped"]
+    }
+}

exercises/practice/split-second-stopwatch/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists