P5172 [Tsinghua Training 2014] Sum

Given positive integers $n$ and $r$, compute: $$\sum_{d=1}^{n}(-1)^{\lfloor d\sqrt{r} \rfloor}$$

The first line contains an integer $t$, indicating that there are $t$ testdata cases. The next $t$ lines each contain two positive integers $n$ and $r$.

Output $t$ lines, each containing one integer representing the answer.

## Constraints |Test Point ID|$t$|$n$|$r$| |:-:|:-:|:-:|:-:| |$1 \sim 3$|$\leqslant 10$|$\leqslant 10^5$|$\leqslant 100$| |$4 \sim 6$|$\leqslant 100$|$\leqslant 10^7$|$\leqslant 1000$| |$7 \sim 10$|$\leqslant 10^4$|$\leqslant 10^9$|$\leqslant 10^4$| Translated by ChatGPT 5