How to decode this sequence losslessly?

Hello. I have a vector, for example: A=[-1 1 0 0 2 -2]. I used this algorithm to encode it: first I put three zeros in the beginning of the vector (zeropad=[0 0 0 -1 1 0 0 2 -2]). then for each symbol in A I use three previous values in 'zeropad' for computing min(abs(subtraction). I subtract the symbol from 3 previuos values and compute [M,I]=min(abs( subtraction); then, I subtract the symbol from the symbol corresponding to index I and send the result to decoder. the result of encoding is [-1 1 0 0 1 -2]. can any one help me to decode the sequence losslessly without sending side info to decoder? thanks for your time and attention.