Distance and Axis

题意翻译

- 在数轴 $OA$ 上 A 的坐标为 $n$，我们想找到一个整数点 B，使得 $\left|\operatorname{dist}(O,B) - \operatorname{dist}(A,B) \right| = k$。$\operatorname{dist}$ 是指两个点的距离。 A,B 都是整数点。 - 有时找不出一个合法的 B，我们可以挪动一下 A。(使 A 的坐标增加或减少1)求挪动 A 的最少次数，使得有一个合法的 B。 - **多组数据**，$0 \le n,k \le 10^6$。 - by 226148

题目描述

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?

输入输出格式

输入格式

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.

输出格式

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

输入输出样例

输入样例 #1

6
4 0
5 8
0 1000000
0 0
1 0
1000000 1000000

输出样例 #1

0
3
1000000
0
1
0

说明

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 $ .