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。

 

  1 #include <cstdio>

  2 #include <map>

  3 #include <cmath>

  4 #include <string>

  5 #include <cstring>

  6 #include <cstdlib>

  7 

  8 using namespace std;

  9 

 10 const int MAXN = 110;

 11 const double INF = 1e30;

 12 const double eps = 1e-8;

 13 const double PI = acos( -1.0 );

 14 

 15 struct Point

 16 {

 17     double x, y;

 18     Point( int x = 0, int y = 0 ): x(x), y(y) {}

 19 };

 20 

 21 struct Coordinate   //空间坐标

 22 {

 23     double x, y, z;

 24 };

 25 

 26 double dist[MAXN][MAXN];

 27 Coordinate C[MAXN];

 28 

 29 double Cha( double a, double b )

 30 {

 31     return (a - b)*(a - b);

 32 }

 33 

 34 double GetDis( Coordinate a, Coordinate b )   //三维空间直线距离

 35 {

 36     return sqrt( Cha( a.x, b.x ) + Cha( a.y, b.y ) + Cha( a.z, b.z ) );

 37 }

 38 

 39 double toRad( double deg )    //角度转弧度

 40 {

 41     return deg / 180.0 * acos( -1.0 );

 42 }

 43 

 44 void get_coord( double R, double lat, double lng, double &x, double &y, double &z ) //经纬度转空间坐标

 45 {

 46     lat = toRad(lat);

 47     lng = toRad(lng);

 48     x = R*cos(lat)*cos(lng);

 49     y = R*cos(lat)*sin(lng);

 50     z = R*sin(lat);

 51     return;

 52 }

 53 

 54 void Floyd( int n )    //弗洛伊德算任意两点最短路

 55 {

 56     for ( int k = 0; k < n; ++k )

 57         for ( int i = 0; i < n; ++i )

 58         for ( int j = 0; j < n; ++j )

 59         {

 60             double temp = dist[i][k] + dist[k][j];

 61             if ( temp < dist[i][j] ) dist[i][j] = temp;

 62         }

 63     return;

 64 }

 65 

 66 int main()

 67 {

 68     int n, m, Q;

 69     double r = 6378;

 70     int cas = 0;

 71     bool flag = false;

 72     while ( scanf( "%d%d%d", &n, &m, &Q ), n || m || Q )

 73     {

 74         map<string, int> Map;

 75         for ( int i = 0; i < n; ++i )

 76         {

 77             char str[100];

 78             Point P;

 79             scanf("%s%lf%lf", str, &P.x, &P.y );

 80             get_coord( r, P.x, P.y, C[i].x, C[i].y, C[i].z );

 81             Map[ str ] = i;

 82         }

 83 

 84         for ( int i = 0; i <= n; ++i )

 85         for ( int j = 0; j <= n; ++j )

 86             dist[i][j] = INF;

 87 

 88         for ( int i = 0; i < m; ++i )

 89         {

 90             char str1[100], str2[100];

 91             scanf( "%s%s", str1, str2 );

 92             int u = Map[ str1 ];

 93             int v = Map[ str2 ];

 94             dist[u][v] = (int)( 2.0 * asin( GetDis( C[u], C[v] ) / ( 2.0 * r ) ) * r + 0.5 );  //四舍五入

 95         }

 96 

 97         Floyd( n );

 98 

 99         if ( flag ) puts("");

100 

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

102 

103         while ( Q-- )

104         {

105             char str1[100], str2[100];

106             scanf( "%s%s", str1, str2 );

107             int u = Map[ str1 ];

108             int v = Map[ str2 ];

109             if ( dist[u][v] >= INF - eps ) puts( "no route exists" );

110             else printf( "%.0f km\n", dist[u][v] );

111         }

112 

113         flag = true;

114     }

115     return 0;

116 }