fix score function

reasoning_gym/algorithmic/string_insertion.py

@@ -5,7 +5,7 @@ https://github.com/yongchao98/CodeSteer-v1.0/blob/main/create_dataset/create_dat
 
 from dataclasses import dataclass
 from random import Random
-from typing import Optional
+from typing import Dict, Optional
 
 from ..factory import ProceduralDataset, register_dataset
 
@@ -26,6 +26,7 @@ Example
     - First, we insert A after ABCD.
     - Even though with the newly inserted 'A' we can obtain the substring BCD[A], we can't use it to insert another character.
     - Lastly, we insert D after DEAB.
+    - Therefore, the final answer is DDABCDAEEDEABD (represented as a string, instead of a list of characters).
 
 Given the following string, provide the answer after inserting the characters according to the pattern: {string}
 """
@@ -79,12 +80,28 @@ class StringInsertionDataset(ProceduralDataset):
                 i += 1
         return "".join(output)
 
+    def score_answer(self, answer: Optional[str], entry: Dict[str, any]) -> float:
+        """Overwrite this method in derived classes if a single oracle answer is not available."""
+        oracle_answer = entry["answer"]
+        if answer is not None:
+            if answer == oracle_answer:
+                return 1.0
+            else:
+                try:
+                    # check if answer is python list of characters
+                    answer = "".join(eval(answer))
+                    if answer == oracle_answer:
+                        return 0.5
+                except Exception as e:
+                    return 0.01
+        return 0.0
+
     def __getitem__(self, idx: int) -> dict:
         """Generate a single String Insertion question"""
         rng = Random(self.seed + idx)
 
         string_length = rng.randint(self.config.min_string_length, self.config.max_string_length)
-        string = [rng.choice(self.vocabulary) for _ in range(string_length)]
+        string = "".join(rng.choice(self.vocabulary) for _ in range(string_length))
 
         answer = self._get_answer(string)