#P6121. Build a tree
Build a tree
Problem Description
HazelFan wants to build a rooted tree. The tree has $n$ nodes labeled $0$ to $n-1$, and the father of the node labeled $i$ is the node labeled $\lfloor\frac{i-1}{k}\rfloor$. HazelFan wonders the size of every subtree, and you just need to tell him the XOR value of these answers.
Input
The first line contains a positive integer $T(1\leq T\leq5)$, denoting the number of test cases.
For each test case:
A single line contains two positive integers $n,k(1\leq n,k\leq10^{18})$.
Output
For each test case:
A single line contains a nonnegative integer, denoting the answer.
2
5 2
5 3
7
6