文章目录 问题 L: Ruined Square 问题 M: Triangular Relationship 问题 L: Ruined Square 题目链接 题目描述 There is a square in the xy-plane. The coordinates of its four vertices are (x1,y1),(x2,y2),(x3,y3) and (x4,y4) in counter-clockwise order. (Assume that the positive x-axis points right, and the...