feat: add Naive Pattern Search algorithm

src/main/java/com/thealgorithms/strings/NaivePatternSearch.java

@@ -0,0 +1,33 @@
+package strings;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Naive Pattern Searching algorithm.
+ * Reference: https://en.wikipedia.org/wiki/String-searching_algorithm#Na%C3%AFve_string_search
+ */
+public class NaivePatternSearch {
+
+    /**
+     * Finds all occurrences of a pattern in a given text using
+     * the naive substring search algorithm.
+     *
+     * @param text    The text in which to search.
+     * @param pattern The pattern to search for.
+     * @return List of starting indices where the pattern is found.
+     */
+    public static List<Integer> search(String text, String pattern) {
+        List<Integer> result = new ArrayList<>();
+        int n = text.length();
+        int m = pattern.length();
+
+        for (int i = 0; i <= n - m; i++) {
+            String sub = text.substring(i, i + m);
+            if (sub.equals(pattern)) {
+                result.add(i);
+            }
+        }
+        return result;
+    }
+}