feat: kata/neutralisation

Author: ParanoidUser

kata/8-kyu/neutralisation/README.md

@@ -1,11 +1,13 @@
 # [Neutralisation](https://www.codewars.com/kata/neutralisation "https://www.codewars.com/kata/65128732b5aff40032a3d8f0")
 
 Given two strings comprised of `+` and `-`, return a new string which shows how the two strings interact in the following way:
+
 - When positives and positives interact, they *remain positive*.
 - When negatives and negatives interact, they *remain negative*.
 - But when negatives and positives interact, they *become neutral*, and are shown as the number `0`.
 
 ### Worked Example
+
 ```
 ("+-+", "+--") ➞ "+-0"
 # Compare the first characters of each string, then the next in turn.
@@ -16,6 +18,7 @@ Given two strings comprised of `+` and `-`, return a new string which shows how
 ```
 
 ### Examples
+
 ```
 ("--++--", "++--++") ➞ "000000"
 
@@ -25,4 +28,5 @@ Given two strings comprised of `+` and `-`, return a new string which shows how
 ```
 
 ### Notes
-The two strings will be the same length.
+
+The two strings will be the same length.

kata/8-kyu/neutralisation/main/Solution.java

@@ -0,0 +1,8 @@
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.IntStream.range;
+
+interface Solution {
+  static String neutralise(String s1, String s2) {
+    return range(0, s1.length()).mapToObj(i -> s1.charAt(i) == s2.charAt(i) ? s1.charAt(i) + "" : "0").collect(joining());
+  }
+}

kata/8-kyu/neutralisation/test/SolutionTest.java

@@ -0,0 +1,38 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class SolutionTest {
+  @ParameterizedTest
+  @CsvSource(textBlock = """
+      '','',''
+      +,+,+
+      -,-,-
+      +,-,0
+      -,+,0
+      -+,++,0+
+      --,-+,-0
+      +--,+--,+--
+      -++,-+-,-+0
+      +-+,-++,00+
+      -++,+--,000
+      -++-,-+-+,-+00
+      --++,++++,00++
+      ---+,-+++,-00+
+      -----,-----,-----
+      --++--,++--++,000000
+      -+-+-+,-+-+-+,-+-+-+
+      +-----+-,---++-++,0--00-+0
+      --+++-+-,+++++---,00+++-0-
+      +++--+---,++----++-,++0--000-
+      -++-+-++-,+-++++---,00+0+000-
+      ---++-+--,-+++--++-,-00+0-+0-
+      ++-++--++-,-+++-++-++,0+0+0000+0
+      +-----+++-,--+-+-++--,0-0-0-++0-
+      -+--+-+---,-+--+-+-+-,-+--+-+-0-
+      """)
+  void sample(String s1, String s2, String expected) {
+    assertEquals(expected, Solution.neutralise(s1, s2));
+  }
+}