Optimal Approach

Algorithm

We can use a more optimised approach using bitwise where we find the XOR in range 1 to L-1 and XOR in range 1 to R. We XOR these to results add cancel out all the common XORs before L, leaving us with the XOR of numbers within the range [L, R].

Define a function that takes an integer n as input and calculates the XOR of numbers from 1 to n based on the pattern:

If N % 4 == 0, the XOR result is N itself.
If N % 4 == 1, the XOR result is 1.
If N % 4 == 2, the XOR result is N + 1.
If N % 4 == 3, the XOR result is 0. Read more about this approach here: Xor of Numbers in given range

For the given range [L, R], calculate the XOR of numbers from 1 to L-1 and 1 to R using the function defined in the previous step.

Return the XOR of the range [L, R] by XORing the results of 1 to L-1 and 1 to R.

Code