POJ 1971 Parallelogram Counting
摘要：
Parallelogram CountingTime Limit:5000MSMemory Limit:65536KTotal Submissions:5605Accepted:1885DescriptionThere are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these points. In other words, find the number of 4-element sub 阅读全文
posted @ 2013-07-17 20:42 lzm风雨无阻 阅读(425) 评论(0) 推荐(0) 编辑
