style: do not clutter the root directory

Author: vil02

.github/workflows/project_structure.yml

@@ -18,5 +18,5 @@ jobs:
           python-version: '3.13'
 
       - name: Check project structure
-        run: python3 check_structure.py
+        run: python3 .github/workflows/scripts/check_structure.py
 ...

.github/workflows/scripts/check_structure.py

@@ -0,0 +1,27 @@
+import pathlib
+import sys
+
+
+def _is_java_file_properly_located(java_file: pathlib.Path) -> bool:
+    main_parents = java_file.parent.parents
+    return (
+        pathlib.Path("src/main/java/com/thealgorithms/") in main_parents
+        or pathlib.Path("src/test/java/com/thealgorithms/") in main_parents
+    )
+
+
+def _find_misplaced_java_files() -> list[pathlib.Path]:
+    return [
+        java_file
+        for java_file in pathlib.Path(".").rglob("*.java")
+        if not _is_java_file_properly_located(java_file)
+    ]
+
+
+if __name__ == "__main__":
+    misplaced_files = _find_misplaced_java_files()
+    if misplaced_files:
+        print("The following java files are not located in the correct directory:")
+        for _ in misplaced_files:
+            print(_)
+        sys.exit(1)