# Poj Solution 3082

```http://poj.org/problem?id=3082

/* @author: */
import java.util.*;
class point
{
int x,y;
point(){x=y=0;}
};

public class Main
{
static int cheng(point a,point b,point c)
{
return (b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y);
}

static int dcheng(point a,point b,point c)
{
return (b.x-a.x)*(c.x-a.x)+(c.y-a.y)*(b.y-a.y);
}

static int in(point []p,int n,point judge)
{
int c,j,k;point up,low,temp;
c=0;j=0;
while(p[j].y==judge.y)j++;
for(;j< n;j=k)
{
k=j+1;
while(p[k%n].y==judge.y&&p[k%n].x>judge.x) k++;
up=p[j];
low=p[k%n];
if(up.y< low.y){    temp=up;up=low;low=temp; }
if(up.y< judge.y||low.y>judge.y)continue;
if(cheng(low,up,judge)<=0&&k==j+1)continue;
c++;
}

return c%2;
}

static point p[][] = new point[30][];
static int len[] = new int[50];

static boolean judge( int a, int b ) {
point p1[] = p[a], p2[] = p[b];
int i, j;
for( i=0; i< len[a]; i++ )
for( j=0; j< len[b]; j++ ) {
if( cheng( p1[i], p2[j], p2[(j+1)%len[b]] ) == 0 &&
dcheng( p1[i], p2[j], p2[(j+1)%len[b]] ) <= 0 )
return true;
}

for( i=0; i< len[b]; i++ )
for( j=0; j< len[a]; j++ )
if( cheng( p2[i], p1[j], p1[(j+1)%len[a]] ) == 0 &&
dcheng( p2[i], p1[j], p1[(j+1)%len[a]] ) <= 0 )
return true;

for( i=0; i< len[a]; i++ )
if( in( p2, len[b], p1[i] ) > 0 )
return true;
for( i=0; i< len[b]; i++ )
if( in( p1, len[a], p2[i] ) > 0 )
return true;
return false;
}

public static void main(String args[]) throws Exception
{
int t, n, j, i, k=1, g;
int ans[] = new int[500];
String w;

Scanner cin = new Scanner( System.in );
t = cin.nextInt();
while( t-- != 0 ) {
n = cin.nextInt();
for( i=0; i< n; i++ ) {
len[i] = cin.nextInt();
p[i] = new point[len[i]];
for( j=0; j< len[i]; j++ ) {
w = cin.next();
g = w.indexOf( ',' );
p[i][j] = new point();
p[i][j].x = Integer.parseInt( w.substring(0,g) );
p[i][j].y = Integer.parseInt( w.substring(g+1) );
}
}
for( i=0; i< n; i++ )
for( j=i+1; j< n; j++ )
if( judge( i, j ) )
System.out.println( "Data Set #" + k );
k++;
System.out.println( "no collisions" );
else {
for( i=0; i< answer; i++ )
System.out.println( ans[i]/100 + " " + ans[i]%100 );
}

}
return;
}
}

```
This entry was posted in poj. Bookmark the permalink.