Missing Number: XOR and Math Solutions

Bit manipulation involves using bitwise operators to perform operations directly on the binary representations of numbers. The fundamental operators are AND, OR, XOR, NOT, left shift, and right shift. These operations execute in O(1) time at the hardware level, making bit manipulation solutions extremely fast. For this problem, we leverage specific bit properties to achieve an elegant solution. XOR is particularly useful: a XOR a equals 0, and a XOR 0 equals a. This property allows us to find si