摘要：
This problem is same as the previous one, but has larger constraints. It was a Sunday morning when the three friends Selena, Shiro and Katie decided t 阅读全文
摘要：
There are n lines l1,l2,…,ln on the 2D-plane. Staring at these lines, Calabash is wondering how many pairs of (i,j) that 1≤i<j≤n and li,lj share at le 阅读全文
摘要：
zThere are n rectangle radar scanners on the ground. The sides of them are all paralleled to the axes. The i-th scanner's bottom left corner is square 阅读全文
摘要：
In the mathematical discipline of graph theory, the line graph of a simple undirected weighted graph G is another simple undirected weighted graph L(G 阅读全文