explain this `def total(): return (1 << 64) - 1` in python

The code def total(): return (1 << 64) - 1 in Python is a function named total that returns a value.

Explanation:

1. (1 << 64) is a bitwise left shift operation where the number 1 (represented in binary as 0000000000000000000000000000000000000000000000000000000000000001) is shifted left by 64 positions. This results in 2^64 (represented as 10000000000000000000000000000000000000000000000000000000000000000) where there are 64 zeroes following the '1'.
2. (2^64) - 1 subtracts 1 from the result of the bitwise left shift. This operation essentially sets all the bits of the binary representation of 2^64 to 1, resulting in a binary number consisting of 64 consecutive 1's (1111111111111111111111111111111111111111111111111111111111111111).
3. This final binary number is converted to its decimal representation, which is the return value of the total function.

In simple terms, the code calculates the total number of combinations possible with a 64-bit binary number, which is the maximum value that can be represented using 64 bits in binary.

Tags: math, bitwise operations