Simulated annealing [JSOI2004] balance / beating and hanging XXX

 

It is limited, at the problem is not the solution, a lot of understanding

 

Thank you for watching this konjac

 

 

Topic : Portal

 

Roughly simulated annealing explain I will not repeat them here, if in doubt please see here

Portal connection

 

code:

#include <. bits / STDC H ++>
 #define Down 0.996 // slowly cooling 
the using  namespace STD;
 int n-;
 struct Node {
 int X;
 int Y;
 int W; 
} Object [ 2005 ]; // able to save the coordinates of the object 
double ANSx, ansy, Use the ANSW command; // final answer 
Double energy ( Double X, Double Y) // according to the knowledge of physics, the smaller the sum, the more stable energy 
{
    Double R & lt = 0 , DX, Dy;
    for ( int A =. 1 ; A <= n-; A ++ ) 
   { 
      DX = X- Object [A] .x; 
      Dy = Y- Object [A] .y; 
      R & lt + = sqrt (DX DX * * + Dy Dy) * Object [A] .W; 
   } 
      return R & lt; 
} 
void SA () // simulated annealing 
{
    Double T = 3000 ; // temperature is sufficiently high 
   the while (T> 1E- 15 ) // slightly greater than 0 
   {
        // generate [-T * RAND_MAX , T * RAND_MAX) random variation range (RAND (): [0, RAND_MAX))
        // RAND () a random number, the maximum value RAND_MAX random 
      doubleANSx + = EX (RAND () * 2 -RAND_MAX) * T; // randomly generated new answer 
      Double EY ansy + = (RAND () * 2 -RAND_MAX) * T;
       Double EW = Energy (EX, EY);
       Double de EW- = Use the ANSW command;
       IF (de < 0 ) // If this answer more preferably, accept 
      { 
         ANSx = EX; 
         ansy = EY; 
         Use the ANSW command = EW; 
      } 
      the else  IF (exp (-DE / T) * and RAND_MAX> RAND ( ))
       // probability exp (-Δt '/ T) accepts S' as a new current solution S.
      // otherwise accepted according to the probability of a polynomial
      { 
         ANSx = EX; 
         ansy = EY; 
      } 
      T * = ; Down 
   } 
} 
void Solve () // probability annealing run a few times, to increase the optimal solution 
{ 
   SA (); 
   SA (); 
   SA (); 
   SA (); 
} 
int main () 
{ 
    CIN >> n-;
     for ( int A = . 1 ; A <= n-; A ++ ) 
    { 
           Scanf ( " % D% D% D " , & Object [A] .x, & Object [a] .y, &Object [A] .W); 
           ANSx + = Object [A] .x; 
           ansy + = Object [A] .y; 
    } 
        ANSx / = n-; // to answer as the initial average 
        ansy / = n-; 
        Use the ANSW command = Energy (ANSx, ansy); 
        Solve (); 
        the printf ( " % .3lf .3lf% \ n- " , ANSx, ansy); // Skip output 
            return  0 ; 
}