Created attachment 87 [details] The image indicates the problem towards the calculation of x-coordinate. This problem is found by a pair of test cases. That is, when the x-coordinate of a piece is increased by 2, the test case does not pass, while the y-coordinate doesn't have this problem. The image is as attached. Steps to reproduce: Run the test case 7. Actual outcome: Test case does not pass. Expect outcome: The test case passes.
Wrong Implementation: result.add(candidate); Correct implementation: delete it