题目网址: http://www.puzzleup.com/2015/ http://www.puzzleup.com/2015/puzzle/?5 答题时限: ８月27日７ＰＭ－比赛结束（约12月16日） 加分时限: ８月27日７ＰＭ－９月１日６：５９ＰＭ 答对可得基本分１００分。答案可上传５次，每改１次答案从基本分扣２０分。　 比赛期间内可随时上传答案，加分时限内答对第ｎ天加（６－ｎ）分　 　　 　　 另依题目的难易有额外加分（如有８０％的人这题答错，答对者加８０分）　　 ◆TEN POINTS You will place 10 points on a paper and you will connect all these points to each other by lines. What can be the minimum number of intersections of these lines? Notes: - There will be a line between every two points. - Only two lines can intersect at an intersection point. - The 10 points themselves will not be considered as intersection points. - Lines are not required to be straight. 你在纸上点下十个点，将这些点彼此之间用线连接起来。 试问这些线的交点最少有几个？ 注: - 任两点之间都有连线。 - 每个交点都仅是两条线的交点。 - 此十点不算入这些交点。 - 线不必要是直的。 -- LPH [acronym] = Let Program Heal us -- New Uncyclopedian Dictionary, Minmei Publishing Co. --

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