URAL 1913 Titan Ruins: Old Generators Are Fine Too

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cmath>
  5 #include <algorithm>
  6 #include <map>
  7 
  8 using namespace std;
  9 
 10 #define LL long long
 11 #define eps 1e-10
 12 #define mxn 1000200
 13 #define mxe 2000020
 14 #define inf 1e12
 15 #define Pi acos( -1.0 )
 16 
 17 //精度
 18 int dcmp( double x ){
 19     if( fabs( x ) < eps ) return 0;
 20     return x < 0 ? -1 : 1;
 21 }
 22 // 点
 23 struct point{
 24     double x, y;
 25     point( double x = 0, double y = 0 ) : x(x), y(y) {}
 26     point operator + ( const point &b ) const{
 27         return point( x + b.x, y + b.y );
 28     }
 29     point operator - ( const point &b ) const{
 30         return point( x - b.x, y - b.y );
 31     }
 32     point operator * ( const double &k ) const{
 33         return point( x * k, y * k );
 34     }
 35     point operator / ( const double &k ) const{
 36         return point( x / k, y / k );
 37     }
 38     bool operator < ( const point &b ) const{
 39         return dcmp( x - b.x ) < 0 || dcmp( x - b.x ) == 0 && dcmp( y - b.y ) < 0;
 40     }
 41     bool operator == ( const point &b ) const{
 42         return dcmp( x - b.x ) == 0 && dcmp( y - b.y ) == 0;
 43     }
 44     double len(){
 45         return sqrt( x * x + y * y );
 46     }
 47 };
 48 typedef point Vector;
 49 // 点积
 50 double dot( Vector a, Vector b ){
 51     return a.x * b.x + a.y * b.y;
 52 }
 53 // 叉积
 54 double cross( Vector a, Vector b ){
 55     return a.x * b.y - a.y * b.x;
 56 }
 57 //两圆相交
 58 void circle_cross( point a, double ra, point b, double rb, point &v1, point &v2 ){
 59     double d = ( a - b ).len();
 60     double da = ( ra * ra + d * d - rb * rb ) / ( 2 * ra * d );
 61     double aa = atan2( (b-a).y, (b-a).x );
 62     double rad = acos( da );
 63     v1 = point( a.x + cos( aa - rad ) * ra, a.y + sin( aa - rad ) * ra );
 64     v2 = point( a.x + cos( aa + rad ) * ra, a.y + sin( aa + rad ) * ra );
 65 }
 66 double R;
 67 point s0, s1, s2;
 68 void solve(){
 69     point ans1, ans2;
 70     if( dcmp( (s0-s1).len() - 2 * R ) <= 0 && dcmp( (s0-s2).len() - 2 * R ) <= 0 ){
 71         ans1 = (s0+s1)/2, ans2 = (s0+s2)/2;
 72     }
 73     else if(dcmp( (s0-s1).len() - 2 * R ) <= 0 || dcmp( (s0-s2).len() - 2 * R ) <= 0){
 74         if( dcmp( (s0-s2).len() - 2 * R ) <= 0 ) swap( s1, s2 );
 75         point v1, v2;
 76         double tmp;
 77         circle_cross( s0, R, s1, R, v1, v2 ); //v1,v2扇形交点
 78         tmp = (s2-v1).len(), ans1 = v1, ans2 = (s2+v1)/2;
 79         if( (s2-v2).len() < tmp )
 80             tmp = (s2-v2).len(), ans1 = v2, ans2 = (s2+v2)/2;
 81         double len1 = (s2-s0).len(), len2 = (s2-s1).len();
 82         point u1 = s0 + ( s2 - s0 ) * (R/len1);
 83         if( (u1-s1).len() <= R ){
 84             if( (s2-u1).len() < tmp )
 85                 tmp = (s2-u1).len(), ans1 = u1, ans2 = (s2+u1)/2;
 86         }
 87         point u2 = s1 + ( s2 - s1 ) * (R/len2);
 88         if( (u2-s0).len() <= R ){
 89             if( (s2-u2).len() < tmp )
 90                 tmp = (s2-u2).len(), ans1 = u2, ans2 = (s2+u2)/2;
 91         }
 92         if( tmp > 2 * R ){
 93             puts( "Death" ); return ;
 94         }
 95     }
 96     else{
 97         if( dcmp( (s1-s2).len() - 2 * R ) > 0 ){
 98             puts( "Death" );return ;
 99         }
100         point v1, v2;
101         circle_cross( s1, R, s2, R, v1, v2 );
102         double tmp;
103         tmp = (s0-v1).len(), ans1 = v1, ans2 = (s0+v1)/2;
104         if( (s0-v2).len() < tmp )
105             tmp = (s0-v2).len(), ans1 = v2, ans2 = (s0+v2)/2;
106         double len1 = (s0-s1).len(), len2 = (s0-s2).len();
107         point u1 = s1 + (s0-s1) * (R/len1), u2 = s2 + (s0-s2)* (R/len2);
108         if( (u1-s2).len() <= R ){
109             if( (s0-u1).len() < tmp )
110                 tmp = (s0-u1).len(), ans1 = u1, ans2 = (u1+s0)/2;
111         }
112         if( (u2-s1).len() <= R ){
113             if( (s0-u2).len() < tmp ){
114                 tmp = (s0-u2).len(), ans1 = u2, ans2 = (u2+s0)/2;
115             }
116         }
117         if( tmp > 2 * R ){
118             puts( "Death" ); return;
119         }
120     }
121     puts( "Now we have enough power");
122     printf( "%.5lf %.5lf\n%.5lf %.5lf\n", ans1.x, ans1.y, ans2.x, ans2.y );
123 }
124 int main(){
125     scanf( "%lf", &R );
126     scanf( "%lf %lf", &s0.x, &s0.y );
127     scanf( "%lf %lf", &s1.x, &s1.y );
128     scanf( "%lf %lf", &s2.x, &s2.y );
129     solve();
130     return 0;
131 }