Pick-up Sticks
Time Limit: 3000MS |
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Memory Limit: 65536K |
Total Submissions: 11043 |
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Accepted: 4119 |
Description
Stan has n sticks of various length. He throws them one at a time to the floor in a random. After finishing throwing, Stan tries to find the top sticks, that's these sticks such that there was no stick on top of th Em. Stan has noticed, the last thrown stick was always on top and he wants to know all the sticks that's on top. Stan sticks is very, very thin such that their thickness can be neglected.
Input
Input consists of a number of cases. The data for each case is start with 1 <= n <= 100000, and the number of the sticks for this case. The following n lines contain four numbers each, these numbers is the planar coordinates of the endpoints of one stick. The sticks is listed in the order in which Stan had thrown them. Assume that there is no more than top sticks. The input is ended by the case with N=0. This case is should not being processed.
Output
For each input case, print one line of output listing the top sticks in the format given in the sample. The top sticks should is listed in order in which they were thrown.
The below illustrates the first case from input.
Sample Input
51 1 4 22 3 3 11-2.0 8 41 4 8 23 3 6-2.030 0 1 11 0 2 12 0 3 10
Sample Output
Top Sticks:2, 4, 5.Top sticks:1, 2, 3.
Hint
Huge input,scanf is recommended.
Source
Waterloo Local 2005.09.17
This is very simple ~ Template Dafa Good ~
Test instructions: Multi-instance testing, each group of n segments, 0 end, to determine how many segments in all segments are not placed in the back line, the number of lines that are pressed to output their numbers (starting from 1),
The format of the output is described in the example ~
1#include <iostream>2#include <cstdio>3#include <cmath>4#include <cstdlib>5#include <cstring>6#include <math.h>7#include <algorithm>8#include <cctype>9#include <string>Ten#include <map> One#include <Set> A #definell Long Long - using namespacestd; - the Const DoubleEPS = 1e-8; - intSgnDoublex) - { - if(Fabs (x) < EPS)return 0; + if(X <0)return-1; - Else return 1; + } A struct Point at { - Doublex, y; - Point () {} -Point (Double_x,Double_y) - { -x =_x; iny =_y; - } toPointoperator-(ConstPoint &b)Const + { - returnPoint (X-b.x,y-b.y); the } * Double operator^(ConstPoint &b)Const $ {Panax Notoginseng returnx*b.y-y*b.x; - } the Double operator*(ConstPoint &b)Const + { A returnx*b.x + y*b.y; the } + }; - $ struct Line $ { - Point s,e; - Line () {} the Line (Point _s,point _e) - {Wuyis =_s; theE =_e; - } Wu }; - BOOLInter (line l1,line L2) About { $ return -Max (l1.s.x,l1.e.x) >= min (l2.s.x,l2.e.x) && -Max (l2.s.x,l2.e.x) >= min (l1.s.x,l1.e.x) && -Max (l1.s.y,l1.e.y) >= min (l2.s.y,l2.e.y) && AMax (l2.s.y,l2.e.y) >= min (l1.s.y,l1.e.y) && +SGN ((l2.s-l1.s) ^ (L1.E-L1.S)) *SGN ((l2.e-l1.s) ^ (L1.E-L1.S)) <=0&& theSGN ((L1.S-L2.S) ^ (L2.E-L2.S)) *SGN ((L1.E-L2.S) ^ (L2.E-L2.S)) <=0; - } $ BOOLvisit[100005]; theLine line[100005]; the intMainvoid) the { the intN; - while(SCANF ("%d",&N), N) in { the DoubleX1,x2,y1,y2; the intsum =N; Aboutmemset (Visit,false,sizeof(visit)); the for(inti =1; I <= N; i++) the { thescanf"%LF%LF%LF%LF",&x1,&y1,&x2,&y2); +Line[i] =Line (Point (X1,y1), point (X2,y2)); -Visit[i] =true; the }Bayi for(inti =1; I <= N; i++) the { the for(intj = i +1; J <= N; J + +) - { - if(Inter (Line[i],line[j])) the { theVisit[i] =false; thesum--; the Break; - } the } the } theprintf"Top Sticks:");94 for(inti =1; I <= N; i++) the { the if(Visit[i]) the {98 if(Sum! =1) About { -sum--;101printf"%d,", i);102 }103 Else104 { theprintf"%d.\n", i);106sum =0;107 Break;108 }109 } the }111 } the return 0;113}
POJ 2653 Pick-up Sticks (judging segment intersection)