feat: kata/get-the-length-of-a-string (#869)

* docs: kata description

* feat: kata/get-the-length-of-a-string

---------

Co-authored-by: ParanoidUser <[email protected]>

Author: github-actions[bot]

kata/7-kyu/get-the-length-of-a-string/README.md

@@ -0,0 +1,20 @@
+# [Get the 𝑟𝑒𝑎𝑙 length of a string](https://www.codewars.com/kata/get-the-length-of-a-string "https://www.codewars.com/kata/599c4b69eb8e49effa000079")
+
+In languages that use [UTF-16 encoding](https://en.wikipedia.org/wiki/UTF-16) for strings (JavaScript, JVM languages like Java, .NET
+languages like C#...), if the code point of a character is larger than `0xFFFF`, it will be treated as two code units.
+
+For example:
+
+The code point of the emoji `🙉` (`U+1F649`, *Hear-No-Evil Monkey*) is `0x1F649`.
+
+```java
+"🙉".length(); // 2
+```
+
+Write a function that returns the *real* length of a string.
+
+```
+"abcd" --> 4
+"🙉" --> 1
+"😸🦌🚀" --> 3
+```

kata/7-kyu/get-the-length-of-a-string/main/Kata.java

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+interface Kata {
+  static int getRealLength(String str) {
+    return str.codePointCount(0, str.length());
+  }
+}

kata/7-kyu/get-the-length-of-a-string/test/SolutionTest.java

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+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
+      abcd, 4
+      中国, 2
+      𝓪𝓫𝓬𝓭, 4
+      𨭎𩷶, 2
+      😸🦌🚀, 3
+      ↓→↑←, 4
+      '\nabc\ndef\n', 9
+      """)
+  void sample(String str, int expected) {
+    assertEquals(expected, Kata.getRealLength(str));
+  }
+}

kata/7-kyu/index.md

@@ -231,6 +231,7 @@
 - [GCD sum](gcd-sum "5dd259444228280032b1ed2a")
 - [Geometry Basics: Dot Product in 3D](geometry-basics-dot-product-in-3d "58e3ea29a33b52c1dc0000c0")
 - [Geometry Basics: Triangle Perimeter in 2D](geometry-basics-triangle-perimeter-in-2d "58e3e62f20617b6d7700120a")
+- [Get the 𝑟𝑒𝑎𝑙 length of a string](get-the-length-of-a-string "599c4b69eb8e49effa000079")
 - [Get the Middle Character](get-the-middle-character "56747fd5cb988479af000028")
 - [Ghostbusters (whitespace removal)](ghostbusters-whitespace-removal "5668e3800636a6cd6a000018")
 - [Go: Stone Scoring](go-stone-scoring "5fdb2ef8656423001c00e648")