A location of at least one fail bit to be repaired in a memory block of a memory is extracted from at least one memory test on the memory block. An available repair resource in the memory for repairing the memory block is obtained. It is checked, using machine learning, whether the at least one fail bit is unrepairable, according to the location of the at least one fail bit, and the available repair resource. When the checking indicates that the at least one fail bit is not unrepairable, it is determined whether a Constraint Satisfaction Problem (CSP) containing a plurality of constraints is solvable. The constraints correspond to the location of the at least one fail bit in the memory block, and the available repair resource. In response to determining that the CSP is not solvable, the memory block is marked as unrepairable or the memory is rejected.