UVa 10075 - Airlines

航线算球面距离，需要经纬度转空间坐标。

任意两点间距离用Floyd求出来，查询时直接查表。

 #include <cstdio>
 #include <map>
 #include <cmath>
 #include <string>
 #include <cstring>
 #include <cstdlib>

 using namespace std;

 const int MAXN = ;
 const double INF = 1e30;
 const double eps = 1e-;
 const double PI = acos( -1.0 );

 struct Point
 {
     double x, y;
     Point( int x = , int y =  ): x(x), y(y) {}
 };

 struct Coordinate   //空间坐标
 {
     double x, y, z;
 };

 double dist[MAXN][MAXN];
 Coordinate C[MAXN];

 double Cha( double a, double b )
 {
     return (a - b)*(a - b);
 }

 double GetDis( Coordinate a, Coordinate b )   //三维空间直线距离
 {
     return sqrt( Cha( a.x, b.x ) + Cha( a.y, b.y ) + Cha( a.z, b.z ) );
 }

 double toRad( double deg )    //角度转弧度
 {
     return deg / 180.0 * acos( -1.0 );
 }

 void get_coord( double R, double lat, double lng, double &x, double &y, double &z ) //经纬度转空间坐标
 {
     lat = toRad(lat);
     lng = toRad(lng);
     x = R*cos(lat)*cos(lng);
     y = R*cos(lat)*sin(lng);
     z = R*sin(lat);
     return;
 }

 void Floyd( int n )    //弗洛伊德算任意两点最短路
 {
     for ( int k = ; k < n; ++k )
         for ( int i = ; i < n; ++i )
         for ( int j = ; j < n; ++j )
         {
             double temp = dist[i][k] + dist[k][j];
             if ( temp < dist[i][j] ) dist[i][j] = temp;
         }
     return;
 }

 int main()
 {
     int n, m, Q;
     double r = ;
     int cas = ;
     bool flag = false;
     while ( scanf( "%d%d%d", &n, &m, &Q ), n || m || Q )
     {
         map<string, int> Map;
         for ( int i = ; i < n; ++i )
         {
             char str[];
             Point P;
             scanf("%s%lf%lf", str, &P.x, &P.y );
             get_coord( r, P.x, P.y, C[i].x, C[i].y, C[i].z );
             Map[ str ] = i;
         }

         for ( int i = ; i <= n; ++i )
         for ( int j = ; j <= n; ++j )
             dist[i][j] = INF;

         for ( int i = ; i < m; ++i )
         {
             char str1[], str2[];
             scanf( "%s%s", str1, str2 );
             int u = Map[ str1 ];
             int v = Map[ str2 ];
             dist[u][v] = (int)( 2.0 * asin( GetDis( C[u], C[v] ) / ( 2.0 * r ) ) * r + 0.5 );  //四舍五入
         }

         Floyd( n );

         if ( flag ) puts("");

         printf( "Case #%d\n", ++cas );

         while ( Q-- )
         {
             char str1[], str2[];
             scanf( "%s%s", str1, str2 );
             int u = Map[ str1 ];
             int v = Map[ str2 ];
             if ( dist[u][v] >= INF - eps ) puts( "no route exists" );
             else printf( "%.0f km\n", dist[u][v] );
         }

         flag = true;
     }
     return ;
 }