当前你的浏览器版本过低，网站已在兼容模式下运行，兼容模式仅提供最小功能支持，网站样式可能显示不正常。
请尽快升级浏览器以体验网站在线编辑、在线运行等功能。

建议使用的浏览器：

谷歌Chrome 火狐Firefox Opera浏览器 微软Edge浏览器 QQ浏览器 360浏览器 傲游浏览器

5646：DZY Loves Partition

题目描述
DZY loves partitioning numbers. He wants to know whether it is possible to partition $n$ into the sum of exactly $k$ distinct positive integers.

After some thinking he finds this problem is Too Simple. So he decides to maximize the product of these $k$ numbers. Can you help him?

The answer may be large. Please output it modulo $10^9+7$.
输入解释
First line contains $t$ denoting the number of testcases.

$t$ testcases follow. Each testcase contains two positive integers $n,k$ in a line.

($1\le t\le 50, 2\le n,k \le 10^9$)
输出解释
For each testcase, if such partition does not exist, please output $-1$. Otherwise output the maximum product mudulo $10^9 + 7$.
输入样例 
4
3 4
3 2
9 3
666666 2
输出样例 
-1
2
24
110888111
提示
In 1st testcase, there is no valid partition.
In 2nd testcase, the partition is $3=1+2$. Answer is $1\times 2 = 2$.
In 3rd testcase, the partition is $9=2+3+4$. Answer is $2\times 3 \times 4 = 24$. Note that $9=3+3+3$ is not a valid partition, because it has repetition.
In 4th testcase, the partition is $666666=333332+333334$. Answer is $333332\times 333334= 111110888888$. Remember to output it mudulo $10^9 + 7$, which is $110888111$.
来自杭电HDUOJ的附加信息
Recommend wange2014
该题目是Virtual Judge题目，来自 杭电HDUOJ
题目来源 BestCoder Round #76 (div.2)
源链接： HDU-5646
最后修改于 2020-10-25T23:24:28+00:00 由爬虫自动更新
共提交 0 次
通过率 --%
时间上限 内存上限
4000/2000MS(Java/Others) 262144/262144K(Java/Others)