Problem Description
Given integers n and start, define an array nums where nums[i] = start + 2 * i (0-indexed) and n equals the length of nums. Return the bitwise XOR of all elements in the array.
Key Insights
- XOR is commutative and associative, meaning the order of operations does not affect the result.
- No need to actually build the array; each element can be computed on-the-fly.
- Iteratively applying the XOR operation for each computed element gives a time-efficient solution.
- The operation uses constant additional space.
Space and Time Complexity
Time Complexity: O(n) Space Complexity: O(1)
Solution
The approach is to initialize a variable result to 0 and iterate from 0 to n-1. In each iteration, calculate the current element using start + 2 * i and then XOR it with the result. Finally, return the result after processing all elements. This method leverages the properties of XOR and does not require extra memory for the array.