Bitwise Tricks

Why it matters

Bit tricks eliminate branches in hot loops. Understanding them shapes performance intuition.

The architecture

x & (x-1) clears lowest set bit; x & -x isolates it.

XOR swap avoids temp variable.

Parity by fold-XOR.

How it works end to end

Kernighan's popcount loop.

Parity via fold and XOR reduction.

Swap without temp using XOR.