Odd Grasshopper

1000ms

262144K

Description:

The grasshopper is located on the numeric axis at the point with coordinate $$$x_0$$$.

Having nothing else to do he starts jumping between integer points on the axis. Making a jump from a point with coordinate $$$x$$$ with a distance $$$d$$$ to the left moves the grasshopper to a point with a coordinate $$$x - d$$$, while jumping to the right moves him to a point with a coordinate $$$x + d$$$.

The grasshopper is very fond of positive integers, so for each integer $$$i$$$ starting with $$$1$$$ the following holds: exactly $$$i$$$ minutes after the start he makes a jump with a distance of exactly $$$i$$$. So, in the first minutes he jumps by $$$1$$$, then by $$$2$$$, and so on.

The direction of a jump is determined as follows: if the point where the grasshopper was before the jump has an even coordinate, the grasshopper jumps to the left, otherwise he jumps to the right.

For example, if after $$$18$$$ consecutive jumps he arrives at the point with a coordinate $$$7$$$, he will jump by a distance of $$$19$$$ to the right, since $$$7$$$ is an odd number, and will end up at a point $$$7 + 19 = 26$$$. Since $$$26$$$ is an even number, the next jump the grasshopper will make to the left by a distance of $$$20$$$, and it will move him to the point $$$26 - 20 = 6$$$.

Find exactly which point the grasshopper will be at after exactly $$$n$$$ jumps.

Input:

The first line of input contains an integer $$$t$$$ ($$$1 \leq t \leq 10^4$$$) — the number of test cases.

Each of the following $$$t$$$ lines contains two integers $$$x_0$$$ ($$$-10^{14} \leq x_0 \leq 10^{14}$$$) and $$$n$$$ ($$$0 \leq n \leq 10^{14}$$$) — the coordinate of the grasshopper's initial position and the number of jumps.

Output:

Print exactly $$$t$$$ lines. On the $$$i$$$-th line print one integer — the answer to the $$$i$$$-th test case — the coordinate of the point the grasshopper will be at after making $$$n$$$ jumps from the point $$$x_0$$$.

Sample Input:

9
0 1
0 2
10 10
10 99
177 13
10000000000 987654321
-433494437 87178291199
1 0
-1 1

Sample Output:

-1
1
11
110
190
9012345679
-87611785637
1
0

Note:

The first two test cases in the example correspond to the first two jumps from the point $$$x_0 = 0$$$.

Since $$$0$$$ is an even number, the first jump of length $$$1$$$ is made to the left, and the grasshopper ends up at the point $$$0 - 1 = -1$$$.

Then, since $$$-1$$$ is an odd number, a jump of length $$$2$$$ is made to the right, bringing the grasshopper to the point with coordinate $$$-1 + 2 = 1$$$.

Informação

Provedor Codeforces

Código CF1607B