題目網址: http://www.puzzleup.com/2014/
http://www.puzzleup.com/2014/puzzle/?255
答題時限: 10月30日7PM-比賽結束(約12月17日)
加分時限: 10月30日7PM-11月5日6:59PM
答對可得基本分100分。答案可上傳5次,每改1次答案從基本分扣20分。
比賽期間內可隨時上傳答案,加分時限內答對第n天加(6-n)分
另依題目的難易有額外加分(如有80%的人這題答錯,答對者加80分)
◆Five Points
http://www.puzzleup.com/2014/img/puzzle/2014/14.jpg
You will connect the five points given in the figure (the vertices of regular
pentagon) by drawing straight lines.
-You will visit each of the points exactly one time.
-You won’t lift your pencil from the paper while drawing.
-You can cross over the lines.
How many diferent shapes can be obtained?
Notes:
-Rotations and reflections will be counted seperately.
-A shape can not be counted as a new shape if it is obtained by just
changing the direction of the drawing betwen the two terminal points.
Four of shapes included in the solution are shown below.
你要將如上圖的五點 (形成一個正五邊形) 畫直線段連接起來。
* 你將經過每個點正好一次。
* 連接時筆尖不離開紙面。
* 直線段之間可以交叉。
試問可以得到多少種圖形?
註:
* 旋轉及鏡像分開計算。
* 若僅僅是改變線段畫的方向則不算新圖形。
以下為其中四種圖形:
http://www.puzzleup.com/2014/img/puzzle/2014/14_ek.jpg