URAL 1030 TITANNIC

计算几何，，，，，，，，，，，，这题太恶心了！！！

求的是球面距离

d(x1,y1,x2,y2)=r*arccos(sin(x1)*sin(x2)+cos(x1)*cos(x2)*cos(y1-y2))

#include <map>

#include <set>

#include <queue>

#include <stack>

#include <math.h>

#include <time.h>

#include <stdio.h>

#include <stdlib.h>

#include <iostream>

#include <limits.h>

#include <string.h>

#include <string>

#include <algorithm>

#define MID(x,y) ( ( x + y ) >> 1 )

#define L(x) ( x << 1 )

#define R(x) ( x << 1 | 1 )

#define BUG puts("here!!!")

#define STOP system("pause")

using namespace std;

const double r = 6875.0/2;

const double pi = acos(-1.0);

double angle_3d(double lng1, double lat1, double lng2, double lat2)

{           //经度，纬度，经度，纬度

    return acos(cos(lat1)*cos(lat2)*cos(lng1 - lng2) + sin(lat1)*sin(lat2));

}

int main()

{

 char s[50];

 

 double x1,x2,x3;

 

 double lng1, lat1, lng2, lat2;

 

 while( ~scanf("%s", s) )

 {

  if( s[0] == '=' ) break;

  for(int i=0; i<8; i++) scanf("%s",s);

  

  scanf("%lf^%lf'%lf\" %s",&x1, &x2, &x3, s);

  lat1 = x1 + x2/60 + x3/3600;

  if( s[0] == 'S' ) lat1 *= -1;

  

  scanf("%s",s);

  

  scanf("%lf^%lf'%lf\" %s",&x1, &x2, &x3, s);

  lng1 = x1 + x2/60 + x3/3600;

  if( s[0] == 'W' ) lng1 *= -1;

  

  for(int i=0; i<5; i++) scanf("%s",s);  // iceberg

 

  scanf("%lf^%lf'%lf\" %s",&x1, &x2, &x3, s);

  lat2 = x1 + x2/60 + x3/3600;

  if( s[0] == 'S' ) lat2 *= -1;

  

  scanf("%s",s);

  

  scanf("%lf^%lf'%lf\" %s",&x1, &x2, &x3, s);

  lng2 = x1 + x2/60 + x3/3600;

  if( s[0] == 'W' ) lng2 *= -1;

  

  double ang = angle_3d(lng1*pi/180, lat1*pi/180, lng2*pi/180, lat2*pi/180);

  double dis = ang * r;

  

  printf("The distance to the iceberg: %.2lf miles.\n", dis);

  

  if( floor(dis+0.005) < 100  )

   printf("DANGER!\n");

 }

return 0;

}