create debug challenge (#4286)

Co-authored-by: Merwane Hamadi <merwanehamadi@gmail.com>
Co-authored-by: symphony <john.tian31@gmail.com>

tests/integration/challenges/debug_code/data/two_sum.py

@@ -0,0 +1,19 @@
+# mypy: ignore-errors
+from typing import List, Optional
+
+
+def two_sum(nums: List, target: int) -> Optional[int]:
+    seen = {}
+    for i, num in enumerate(nums):
+        complement = target - num
+        if complement in seen:
+            return [seen[complement], i]
+        seen[num] = i
+    return None
+
+
+# Example usage:
+nums = [2, 7, 11, 15]
+target = 9
+result = two_sum(nums, target)
+print(result)  # Output: [0, 1]

tests/integration/challenges/debug_code/data/two_sum_tests.py

@@ -0,0 +1,30 @@
+# mypy: ignore-errors
+# we need a new line at the top of the file to avoid a syntax error
+
+
+def test_two_sum(nums, target, expected_result):
+    # These tests are appended to the two_sum file so we can ignore this error for now
+    result = two_sum(nums, target)
+    print(result)
+    assert (
+        result == expected_result
+    ), f"AssertionError: Expected the output to be {expected_result}"
+
+
+# test the trivial case with the first two numbers
+nums = [2, 7, 11, 15]
+target = 9
+expected_result = [0, 1]
+test_two_sum(nums, target, expected_result)
+
+# test for ability to use zero and the same number twice
+nums = [2, 7, 0, 15, 12, 0]
+target = 0
+expected_result = [2, 5]
+test_two_sum(nums, target, expected_result)
+
+# test for first and last index usage and negative numbers
+nums = [-6, 7, 11, 4]
+target = -2
+expected_result = [0, 3]
+test_two_sum(nums, target, expected_result)