[ABC213A] Bitwise Exclusive Or

ID: 18498

传统题

2000ms

1024MiB

难度: 1

上传者:

Score : $100$ points

Problem Statement

You are given integers $A$ and $B$ between $0$ and $255$ (inclusive). Find a non-negative integer $C$ such that $A \text{ xor }C=B$ .

It can be proved that there uniquely exists such $C$ , and it will be between $0$ and $255$ (inclusive).

What is bitwise $\mathrm{XOR}$?

The bitwise $\mathrm{XOR}$ of integers $A$ and $B$ , $A\ \mathrm{XOR}\ B$ , is defined as follows:

When $A\ \mathrm{XOR}\ B$ is written in base two, the digit in the $2^k$ 's place ( $k \geq 0$ ) is $1$ if exactly one of $A$ and $B$ is $1$ , and $0$ otherwise.

For example, we have $3\ \mathrm{XOR}\ 5 = 6$ (in base two: $011\ \mathrm{XOR}\ 101 = 110$ ).

Input is given from Standard Input in the following format:

$A$ $B$

Print the answer.

3 6

When written in binary, $3$ will be $11$ , and $5$ will be $101$ . Thus, their $\text{xor}$ will be $110$ in binary, or $6$ in decimal.

In short, $3 \text{ xor } 5 = 6$ , so the answer is $5$ .

10 12