Their bitwise multiplication (aka "logical and") is the following string:
0001001010
Their bitwise addition (=subtraction, aka "logical xor") is the following string:
1100110101
"Bitwise" means you perform the operation separately for each corresponding bit. The first bit of the first string is 0, the first bit of the second string is 1, their product is 0, and their sum is 1 - these are the first bits of the corresponding result bitstrings, and so on.
Note that 1+1 is defined as 0, i.e. you "overflow the bit value", although this is not even important for the problem at hand.
Consider two bitstrings:
0101101011
1001011110
Their bitwise multiplication (aka "logical and") is the following string:
0001001010
Their bitwise addition (=subtraction, aka "logical xor") is the following string:
1100110101
"Bitwise" means you perform the operation separately for each corresponding bit. The first bit of the first string is 0, the first bit of the second string is 1, their product is 0, and their sum is 1 - these are the first bits of the corresponding result bitstrings, and so on.
Note that 1+1 is defined as 0, i.e. you "overflow the bit value", although this is not even important for the problem at hand.
thanks very clear