Add duplicate checker script to detect duplicate files.

check_duplicates.py

@@ -0,0 +1,38 @@
+import hashlib
+import os
+
+def hash_file(file_path):
+    """Returns the SHA-1 hash of the file."""
+    hash_sha1 = hashlib.sha1()
+    with open(file_path, "rb") as f:
+        for chunk in iter(lambda: f.read(4096), b""):
+            hash_sha1.update(chunk)
+    return hash_sha1.hexdigest()
+
+def check_duplicates(base_dir=".", extensions=(".cpp", ".java", ".py")):
+    """Checks for duplicate files by content hash in the given directory."""
+    hashes = {}
+    duplicates = []
+
+    for root, _, files in os.walk(base_dir):
+        for file in files:
+            if file.endswith(extensions):
+                file_path = os.path.join(root, file)
+                file_hash = hash_file(file_path)
+
+                if file_hash in hashes:
+                    duplicates.append((file_path, hashes[file_hash]))
+                else:
+                    hashes[file_hash] = file_path
+
+    return duplicates
+
+if __name__ == "__main__":
+    duplicates = check_duplicates()
+    if duplicates:
+        print("Duplicate files found:")
+        for dup in duplicates:
+            print(f"{dup[0]} is a duplicate of {dup[1]}")
+        exit(1)  # Exit with error to flag as duplicate in GitHub Actions
+    else:
+        print("No duplicates found.")