feat: kata/stones-on-the-table

Author: ParanoidUser

kata/7-kyu/stones-on-the-table/README.md

@@ -2,12 +2,13 @@
 
 There are some stones on Bob's table in a row, and each of them can be red, green or blue, indicated by the characters `R`, `G`, and `B`.
 
-Help Bob find the minimum number of stones he needs to remove from the table so that the stones in each pair of adjacent stones have different colors.
+Help Bob find the minimum number of stones he needs to remove from the table so that the stones in each pair of adjacent stones have
+different colors.
 
 Examples:
 
 ```
 "RGBRGBRGGB" => 1
 "RGGRGBBRGRR" => 3
 "RRRRGGGGBBBB" => 9
-```
+```

kata/7-kyu/stones-on-the-table/main/Solution.java

@@ -0,0 +1,5 @@
+interface Solution {
+  static int solve(String stones) {
+    return stones.length() - stones.replaceAll("(.)\\1+", "$1").length();
+  }
+}

kata/7-kyu/stones-on-the-table/test/SolutionTest.java

@@ -0,0 +1,18 @@
+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 = """
+      RGBRGB, 0
+      RRGGBB, 3
+      BGRBBGGBRRR, 4
+      GBBBGGRRGRB, 4
+      GBRGGRBBBBRRGGGB, 7
+      """)
+  void sample(String stones, int duplicates) {
+    assertEquals(duplicates, Solution.solve(stones));
+  }
+}