feat: kata/death-by-coffee

docs/README.md

@@ -25,7 +25,7 @@ slug.
 
 | [1 kyu](/kata/1-kyu/index.md) | [2 kyu](/kata/2-kyu/index.md) | [3 kyu](/kata/3-kyu/index.md) | [4 kyu](/kata/4-kyu/index.md) | [5 kyu](/kata/5-kyu/index.md) | [6 kyu](/kata/6-kyu/index.md) | [7 kyu](/kata/7-kyu/index.md) | [8 kyu](/kata/8-kyu/index.md) | [beta](/kata/beta/index.md) | [retired](/kata/retired/index.md) |
 |:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:---------------------------:|:---------------------------------:|
-| 0 | 1 | 2 | 26 | 48 | 439 | 603 | 226 | 56 | 82 |
+| 0 | 1 | 2 | 26 | 48 | 440 | 603 | 226 | 56 | 82 |
 
 **Note:** The source code is written in Java 17 and may use language features that are incompatible
 with Java 8, 11.

kata/6-kyu/death-by-coffee/README.md

@@ -0,0 +1,64 @@
+# [Death by Coffee](https://www.codewars.com/kata/death-by-coffee "https://www.codewars.com/kata/57db78d3b43dfab59c001abe")
+
+## Background
+
+I drink too much coffee. Eventually it will probably kill me.
+
+*Or will it...?*
+
+Anyway, there's no way to know.
+
+*Or is there...?*
+
+## The Discovery of the Formula
+
+I proudly announce my discovery of a formula for measuring the life-span of coffee drinkers!
+
+For
+
+* ```h``` is a health number assigned to each person (8 digit date of birth YYYYMMDD)
+* ```CAFE``` is a cup of *regular* coffee
+* ```DECAF``` is a cup of *decaffeinated* coffee
+
+To determine the life-time coffee limits:
+
+* Drink cups of coffee (i.e. add to ```h```) until any part of the health number includes `DEAD`
+* If the test subject can survive drinking <u>five thousand</u> cups without being ```DEAD``` then coffee has no ill effect on them
+
+# Kata Task
+
+Given the test subject's date of birth, return an array describing their life-time coffee limits
+
+```[ regular limit , decaffeinated limit ]```
+
+## Notes
+
+* The limits are ```0``` if the subject is unaffected as described above
+
+* At least 1 cup must be consumed (Just thinking about coffee cannot kill you!)
+
+# Examples
+
+* <b>John</b> was born 19/Jan/1950 so ```h=19500119```. His coffee limits are ```[2645, 1162]``` which is only about 1 cup per week. You
+  better cut back John...How are you feeling? You don't look so well.
+
+
+* <b>Susan</b> (11/Dec/1965) is unaffected by decaffeinated coffee, but regular coffee is very bad for her ```[111, 0]```. Just stick to the
+  decaf Susan.
+
+
+* <b>Elizabeth</b> (28/Nov/1964) is allergic to decaffeinated coffee. Dead after only 11 cups ```[0, 11]```. Read the label carefully Lizzy!
+  Is it worth the risk?
+
+
+* <b>Peter</b> (4/Sep/1965) can drink as much coffee as he likes ```[0, 0]```. You're a legend Peter!!
+
+<hr>
+
+Hint: https://en.wikipedia.org/wiki/Hexadecimal
+
+<hr>
+
+<div style='color:red'>
+*Note: A life-span prediction formula this accurate has got to be worth a lot of money to somebody! I am willing to sell my copyright to the highest bidder. Contact me via the discourse section of this Kata.*
+</div>

kata/6-kyu/death-by-coffee/main/Dinglemouse.java

@@ -0,0 +1,14 @@
+import static java.util.stream.IntStream.range;
+
+import java.util.function.ToIntBiFunction;
+
+interface Dinglemouse {
+  static int[] coffeeLimits(int year, int month, int day) {
+    ToIntBiFunction<int[], Integer> limit = (h, c) -> range(1, 5000)
+        .filter(i -> Integer.toHexString(h[0] += c).contains("dead")).findFirst().orElse(0);
+    return new int[]{
+        limit.applyAsInt(new int[]{10000 * year + 100 * month + day}, 0xCAFE),
+        limit.applyAsInt(new int[]{10000 * year + 100 * month + day}, 0xDECAF)
+    };
+  }
+}

kata/6-kyu/death-by-coffee/test/DinglemouseTest.java

@@ -0,0 +1,18 @@
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class DinglemouseTest {
+  @ParameterizedTest
+  @CsvSource(textBlock = """
+      1965, 9, 4, 0, 0
+      1964, 11, 28, 0, 11
+      1965, 12, 11, 111, 0
+      1950, 1, 19, 2645, 1162
+      1880, 3, 1, 0, 3909
+      """)
+  void sample(int y, int m, int d, int cafe, int decaf) {
+    assertArrayEquals(new int[]{cafe, decaf}, Dinglemouse.coffeeLimits(y, m, d));
+  }
+}

kata/6-kyu/index.md

@@ -106,6 +106,7 @@
 - [Data compression using run-length encoding](data-compression-using-run-length-encoding)
 - [Data Reverse](data-reverse)
 - [Dead Ants](dead-ants)
+- [Death by Coffee](death-by-coffee)
 - [Decode the Morse code](decode-the-morse-code)
 - [Decode the woofs!](decode-the-woofs)
 - [Delete occurrences of an element if it occurs more than n times](delete-occurrences-of-an-element-if-it-occurs-more-than-n-times)