XOR with a left-shifted 1 is the clean answer here.
Start by clarifying the problem and edge cases, then explain the bitwise XOR approach using a mask with 1 shifted left by the given position. Walk through a concrete example, and finally analyze the time and space complexity as O(1).
Pro tip: Mention that XOR with a mask is the idiomatic way to flip a bit, and note that this works for any non-negative integer without needing to know its bit length. Also, briefly discuss potential pitfalls like assuming 32-bit integers or using signed shifts.
Confirm that the bit position is zero-based and that only that bit should be flipped, leaving all other bits unchanged. Ask about integer size assumptions (e.g., 32-bit vs arbitrary precision).
Describe creating a mask by left-shifting 1 by the given position, then XORing the original number with the mask. This flips the target bit because XOR with 1 toggles, while XOR with 0 leaves bits unchanged.
Pick a simple number (e.g., 5, binary 101) and a position (e.g., 1). Show the mask (1 << 1 = 2, binary 010), then 5 ^ 2 = 7 (binary 111), demonstrating the bit flip.
State that both time and space complexity are O(1) because the operation involves a constant number of bitwise operations and no additional data structures.
Mention handling position 0, large positions (within integer bounds), and that the same logic applies to signed integers if using unsigned semantics. Optionally, note that other bitwise tricks (like addition/subtraction) are less clear.
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