OJ-Problems-Source/HDOJ/3263_autoAC.cpp

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cmath>
using namespace std;
typedef struct pnode
{
    double x,y,d;
    pnode( double a, double b ) {x = a;y = b;}
    pnode(){};
}point;
point H[ 21 ];
point C[ 21 ];
point P0,Pn;
typedef struct lnode
{
    double x,y,dx,dy,d;
    int    id,hit,sign;
    lnode( point a, point b ) {x = a.x;y = a.y;dx = b.x-a.x;dy = b.y-a.y;}
    lnode(){};
}line;
double dist( point a, point b )
{
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
double dist( point a, line l )
{
    return fabs(l.dx*(a.y-l.y)-l.dy*(a.x-l.x))/sqrt(l.dx*l.dx+l.dy*l.dy);
}
double crossproduct( point a, point b, point c )
{
    return (b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y);
}
bool cmp1( point a, point b )
{
    if ( a.x == b.x ) return a.y < b.y;
    else return a.x < b.x;
}
bool cmp2( point a, point b )
{
    double cp = crossproduct( P0, a, b );
    if ( cp == 0 ) return a.d < b.d;
    else return cp > 0;
}
double Graham( int N )
{
    sort( C+0, C+N, cmp1 );
    P0 = C[0];
    for ( int i = 1 ; i < N ; ++ i )
        C[i].d = dist( P0, C[i] );
    sort( C+1, C+N, cmp2 );
    int top = 2;
    for ( int i = 3 ; i < N ; ++ i ) {
        while ( top > 0 && crossproduct( C[top-1], C[top], C[i] ) <= 0 ) -- top;
        C[++ top] = C[i];
    }
    C[++ top] = C[0];
       int    L = 0,R = 1;
       double D = 500.000;
       do{
        while ( crossproduct( C[R], C[L], C[(L+1)%top] ) <= crossproduct( C[(R+1)%top], C[L], C[(L+1)%top] ) )
            R = (R+1)%top;
        D = min( D, dist( C[R], line( C[L], C[(L+1)%top] ) ) );
        L = (L+1)%top;
    }while ( L );
    return D;
}
bool l_cross_s( line b, line a )
{
    double t1 = b.dx*(a.y-b.y)-b.dy*(a.x-b.x);
    double t2 = b.dx*(a.y+a.dy-b.y)-b.dy*(a.x+a.dx-b.x);
    return t1*t2 < 0;
}
bool s_cross_s( line a, line b )  
{  
    double t1 = 0.0+a.dx*(b.y-a.y)-a.dy*(b.x-a.x);  
    double t2 = 0.0+a.dx*(b.y+b.dy-a.y)-a.dy*(b.x+b.dx-a.x);  
    double t3 = 0.0+b.dx*(a.y-b.y)-b.dy*(a.x-b.x);  
    double t4 = 0.0+b.dx*(a.y+a.dy-b.y)-b.dy*(a.x+a.dx-b.x);  
    return (t1*t2 < 0)&&(t3*t4 < 0);  
}
bool on( point p, line l )  
{  
    if ( l.dx*(p.y-l.y)-l.dy*(p.x-l.x) == 0 )  
    if ( (p.x-l.x)*(p.x-l.x-l.dx) <= 0 )  
    if ( (p.y-l.y)*(p.y-l.y-l.dy) <= 0 )  
        return true;  
    return false;  
}  
bool in( point p, point* P, int n )  
{  
    double d[4][2] = {-101,-103,-103,101,101,-103,101,103};  
    for ( int t = 0 ; t < 4 ; ++ t ) {  
        line s1 = line( p, point( d[t][0], d[t][1] ) );  
        int  count = 0;  
        for ( int i = 0 ; i < n ; ++ i ) {  
            line s2 = line( P[i], P[i+1] );  
            if ( on( p, s2 ) ) return true;  
            if ( s_cross_s( s1, s2 ) ) count ++;  
            if ( on( P[i], s1 ) && l_cross_s( s1, line( P[i+1], P[(i-1+n)%n] ) ) ) count ++;  
        }
        if ( count%2 == 0 ) return false;   
    }  
    return true;  
}  
point crosspoint( line l, line m )
{
    point a = point( m.x, m.y );
    point b = point( m.x+m.dx, m.y+m.dy );
    if ( m.dx*l.dy == m.dy*l.dx ) {
        if ( dist( point( l.x, l.y ), a ) < dist( point( l.x, l.y ), b ) )
            return a;
        else return b;
    }else {
        double a1 = -l.dy,b1 = l.dx,c1 = l.dx*l.y-l.dy*l.x;
        double a2 = -m.dy,b2 = m.dx,c2 = m.dx*m.y-m.dy*m.x;
        double x = (c1*b2-c2*b1)/(a1*b2-a2*b1);
        double y = (c1*a2-c2*a1)/(b1*a2-b2*a1);
        return point( x, y );
    } 
}
double Calcul( int N )
{
    H[N] = H[0];
    point  X[ 21 ];
    double D = 0.0;
    for ( int i = 0 ; i < N ; ++ i )
    for ( int j = i+1 ; j < N ; ++ j ) {
        line l = line( H[i], H[j] );
        int S = 0;
        for ( int k = 0 ; k < N ; ++ k ) {
            line m = line( H[k], H[k+1] );
            if ( l_cross_s( l, m ) )
                X[S ++] = crosspoint( l, m );
        }
        X[S ++] = H[i];
        X[S ++] = H[j];
        P0 = point( -101, -103 );
        for ( int k = 0 ; k < S ; ++ k )
            X[k].d = dist( P0, X[k] );
        sort( X, X+S, cmp2 );
        double sum = 0.0;
        int    fla = 0;
        for ( int i = 1 ; i < S ; ++ i ) {
            if ( in( point( (X[i-1].x+X[i].x)/2, (X[i-1].y+X[i].y)/2 ), H, N ) ) {
                if ( fla ) sum += dist( X[i-1], X[i] );
                else sum = dist( X[i-1], X[i] );
                D = max( D, sum );
                fla = 1;
            }
        }
    }
    return D;
}
int main()
{
    int T,N,M;
    while ( scanf("%d",&T) != EOF ) 
    while ( T -- ) {
        scanf("%d",&N);
        for ( int i = 0 ; i < N ; ++ i )
            scanf("%lf%lf",&H[i].x,&H[i].y);
        scanf("%d",&M);
        for ( int i = 0 ; i < M ; ++ i )
            scanf("%lf%lf",&C[i].x,&C[i].y);
        double d = Graham( M );
        double D = Calcul( N );
        if ( d <= D ) printf("legal\n");
        else printf("illegal\n");
    }
    return 0;
}