A13725. Distance and Axis

We have a point $A$ with coordinate $x = n$ on $OX$ -axis. We'd like to find an integer point $B$ (also on $OX$ -axis), such that the absolute difference between the distance from $O$ to $B$ and the distance from $A$ to $B$ is equal to $k$ .

The description of the first test case. Since sometimes it's impossible to find such point $B$ , we can, in one step, increase or decrease the coordinate of $A$ by $1$ . What is the minimum number of steps we should do to make such point $B$ exist?

The first line contains one integer $t$ ( $1 \le t \le 6000$ ) — the number of test cases.

The only line of each test case contains two integers $n$ and $k$ ( $0 \le n, k \le 10^6$ ) — the initial position of point $A$ and desirable absolute difference.

For each test case, print the minimum number of steps to make point $B$ exist.

In the first test case (picture above), if we set the coordinate of $B$ as $2$ then the absolute difference will be equal to $|(2 - 0) - (4 - 2)| = 0$ and we don't have to move $A$ . So the answer is $0$ .

In the second test case, we can increase the coordinate of $A$ by $3$ and set the coordinate of $B$ as $0$ or $8$ . The absolute difference will be equal to $|8 - 0| = 8$ , so the answer is $3$ .