集训队作业解题报告

1、题目来源Ural 1509 Domino Recognition问题描述一块 1*2 的骨牌（每个 1*1 的骨牌边长在区间1,100内），可有数字 0 到 6。刻法如下：输入两块骨牌上 n 个点的坐标(1n12)，输出所有可能的骨牌数值。（确保存在合法的分布）算法计算所有两点点对的距离，求出最大值和最小值的比即可确定。n=2 和 n=7 的情况需要单独处理。算法证明模拟算法，无需证明。算法实现没有实现上。源代码const maxn=12;zero=1e-4;var dd,max,min:extended;i,j,k,n:long;d,rray1.maxn,1.maxnof extended;

2、x,y:array1.maxnof extended; beginreadln(n);for i:=1 to n for i:=1 to nfor j:=1 todo readln(xi,yi); don dodi,j:=(sqr(xi-xj)+sqr(yi-yj); max:=d1,2; min:=d1,2;for i:=1 to n-1 dofor j:=i+1 to ndo beginthen max:=di,j;hen min:=di,j;if if end;case ndi,jmaxdi,jmof1:begin wri2:beginn(0 1); halt; end;if d1,2+

3、zero5000+zero then begin wri wrin(0 2);wrin(1 1); halt;end;3:beginn(11); halt; end;if ififabs(d1,2-d2,3)zeroabs(d1,3-d2,3)zeroabs(d1,2-d1,3)zerothen thenthenbegin beginbeginwri wriwrin(0n(0n(03);3);3);halt; end; halt; end;halt; end;wrin(1 2); halt;end; 4:beginif maxmin*4then wrin(0 4)/sqrt(2)else if

4、 maxmin*10then wri else wrihalt; end;5:beginn(2n(12)/ sqrt(5)3); / sqrt(13)if maxmin*4.5then wrin(0 5)/2else if maxmin*8then wri else wrihalt; end;6:beginif maxmin*12n(1n(24)3);/sqrt(13/2)sqrt(20)then if maxmin*9then wrielse wrin(0n(26)4)/sqrt(8)sqrt(10)else if maxmin*23 then begin wri else begink:=

5、0;for i:=1n(1n(35)3);/sqrt(13)sqrt(20)n(1 6); halt; endto n-1 dofor j:=i+1 to n doif di,jmin*30n(3 4) else wrin(25);then wrin(2 6)/sqrt(40)else if maxmin*15then wri else wrihalt; end;9:beginif maxmin*30n(3n(45)4);/sqrt(20)sqrt(10)then wri else wri halt;end;10:beginn(4n(35)6);/sqrt(20)/ sqrt(40)if ma

6、xmin*30then wrin(5 5)/ sqrt(20)else wri halt;end; 11:begin wri 12:begin wri end;end.n(4 6);/ sqrt(40)n(5 6); halt;n(6 6); halt;end;end;原题描述：1509. Domino RecognitionTime Limit: 1.0 second Memory Limit: 16 MBIn Vovans casino, all croupiers are robots. Once a thought occurred toVovant it would be usefu

7、l if robotst play dominoes with cntscould recognize the type of a bone before it is turned over,t is, whena bones on a table with its face down. Fortunay, it issiblesince the dots on bones are diamonds, and diamonds can be seen in X-rays. Moving a manipulator over a bone, a robot can direct X-rays t

8、hrough itto a camera locatedhe robots leg. Using the obtained photo, a spelprogram must recognize the type of the bone. Now try to guess who will write this program.A bone is a rectangle of size L 2L (1 L 100) comed of two squares.In each of the squares, there are from 0 to 6 dots arrangedhe classic

9、alway. In order to describe the arrangements of dots on a square, we considera smaller square with the same center whose sides are twi the sides of the bigger square and parallel to them.hortern1 dot is puthe center of the square2 dots are situated at the lower left and upper right corners of the sm

10、allersquare 3 dots of the 4 dots5 dots of the(we ameta bone is oriented vertically) he same way as 2 dots plus a doare arranged squareare at the four are arranged squarethe centercorners of the smaller square he same way as 4 dots plus a dothe center6 dots: four dots are puthe corners of the smaller

11、square and two t are paralleldots are at the middles of the sides of the smaller square to the long sides of the bone.Your task is toyze a photo of a bone. It is knownt the photo showsall dots of exactly one bone. The plane of the parallel to the tablerface; there are no distortions, but the bone ma

12、y be arbitrarily rocameras receiver isor otheredhe plane of thetable.t fett the bone on the tableis turned over.InputThe 12).line contains the number of dots seenhe photo N (1 NThe next N lines contahe coordinates of these dots. Thecoordinates are accurate to 0.0001. Absolute values of coordinates exceed 2000. The photo shows the real size of the bone.otOutputegers A and B (A B), which are the numbers of dotsOutputhetwo squares of the bone. If several answers aresible, they should begiven correct.he lexicograph