DigDecry

DigDecry is a digital decryption application
Every time you guess a number, a number of A and B will be given according to the number, where the number in the A kilometer represents the number of correct numbers, and the number in front of B represents the number of correct numbers but the number of incorrect locations. For example, if the correct answer is 5234, and the guesser guesses 5346, it is 1A2B. One of the 5's is in the right position, which is recorded as 1A, and the two numbers 3 and 4 are correct, but the position is wrong, so it is recorded as 2B. , together is 1A2B.
Until the guess is correct (ie 4A0B)