server/tasks/task_easy.py

# server/tasks/task_easy.py
TASK_EASY = {
    "task_id": "task_easy",
    "difficulty": "easy",
    "num_tests": 4,
    "description": (
        "Fix the off-by-one error in the `find_max_subarray_sum` function. "
        "It should return the maximum contiguous subarray sum (Kadane's algorithm). "
        "Currently it misses the last element."
    ),
    # The broken version the agent sees
    "buggy_code": """\
def find_max_subarray_sum(nums: list[int]) -> int:
    if not nums:
        return 0
    max_sum = current_sum = nums[0]
    # BUG: range stops one short
    for i in range(1, len(nums) - 1):
        current_sum = max(nums[i], current_sum + nums[i])
        max_sum = max(max_sum, current_sum)
    return max_sum
""",
    # The correct solution (used by task_generator)
    "clean_code": """\
def find_max_subarray_sum(nums: list[int]) -> int:
    if not nums:
        return 0
    max_sum = current_sum = nums[0]
    for i in range(1, len(nums)):
        current_sum = max(nums[i], current_sum + nums[i])
        max_sum = max(max_sum, current_sum)
    return max_sum
""",
    # Hidden test suite — agent never sees this directly
    "test_suite": """\
def test_basic():
    assert find_max_subarray_sum([-2, 1, -3, 4, -1, 2, 1, -5, 4]) == 6

def test_all_negative():
    assert find_max_subarray_sum([-3, -1, -2]) == -1

def test_single():
    assert find_max_subarray_sum([42]) == 42

def test_empty():
    assert find_max_subarray_sum([]) == 0
""",
}