feat: add Partitions utility class

Author: Flashky

src/main/java/com/adventofcode/flashk/common/Partitions.java

@@ -0,0 +1,34 @@
+package com.adventofcode.flashk.common;
+
+import module java.base;
+
+/// Utility class to make partitions of Strings, Lists etc.
+public class Partitions {
+
+    private Partitions() {}
+
+    /// Creates a List of Strings with the given partition size
+    ///
+    /// Example:
+    ///
+    /// ```
+    /// Partitions.fromString("abcd", 1); // ["a","b","c","d"]
+    /// Partitions.fromString("abcd", 2); // ["ab","cd"]
+    /// Partitions.fromString("abcd", 3); // ["abc","d"]
+    /// ```
+    /// @param text the text to create the partition from
+    /// @param partitionSize the size of the partition
+    /// @return a list containing all the partitions created from the text.
+    public static List<String> fromString(String text, int partitionSize) {
+        List<String> results = new ArrayList<>();
+
+        int length = text.length();
+
+        for (int i = 0; i < length; i += partitionSize) {
+            results.add(text.substring(i, Math.min(length, i + partitionSize)));
+        }
+
+        return results;
+    }
+
+}

src/test/java/com/adventofcode/flashk/common/PartitionsTest.java

@@ -0,0 +1,51 @@
+package com.adventofcode.flashk.common;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static java.lang.IO.println;
+
+import module java.base;
+import org.junit.jupiter.api.Test;
+
+class PartitionsTest {
+
+    @Test
+    void fromStringPartitionSize1() {
+
+        List<String> result = Partitions.fromString("abcd", 1);
+
+        assertEquals(4, result.size());
+        assertEquals("a", result.get(0));
+        assertEquals("b", result.get(1));
+        assertEquals("c", result.get(2));
+        assertEquals("d", result.get(3));
+    }
+
+    @Test
+    void fromStringPartitionSize2() {
+
+        List<String> result = Partitions.fromString("abcd", 2);
+
+        assertEquals(2, result.size());
+        assertEquals("ab", result.get(0));
+        assertEquals("cd", result.get(1));
+
+    }
+
+    @Test
+    void fromStringPartitionSize3() {
+        List<String> result = Partitions.fromString("abcd", 3);
+
+        assertEquals(2, result.size());
+        assertEquals("abc", result.get(0));
+        assertEquals("d", result.get(1));
+    }
+
+    @Test
+    void fromStringPartitionSize4() {
+        List<String> result = Partitions.fromString("abcd", 4);
+
+        assertEquals(1, result.size());
+        assertEquals("abcd", result.getFirst(0));
+    }
+
+}