Bit Manipulation Tricks Summary

Here's a quick reference of the most useful bit tricks:

• Power of 2 check: $n > 0$ and $n \& (n-1) = 0$

• Clear rightmost set bit: $n \& (n-1)$

• Isolate rightmost set bit: $n \& (-n)$

• Count set bits: loop with $n := n \& (n-1)$

• Find unique element (all others appear twice): XOR all numbers

• Generate all subsets: iterate masks from $0$ to $2^n - 1$

Memorize these patterns. They appear frequently in coding interviews.