HDU 2899Strange fuction(模拟退火)-白红宇

HDU 2899Strange fuction(模拟退火)

阅读量：6036 次

发布时间：2019-06-20

本文共 1143 字，大约阅读时间需要 3 分钟。

题意

求 $F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100)$的最小值

Sol

强上模拟退火，注意eps要开大！

/**/#include
     
      #include
      
       #include
       
        #include
        
         #include
         
          using namespace std;const int MAXN = 1e6 + 10;const double eps = 1e-10, Dlt = 0.98;int T;double Y, Best;double F(double x) {    return 6 * x * x * x * x * x * x  * x + 8 * x * x * x * x * x * x + 7 * x * x * x + 5 * x * x - Y * x;}double getrand(double T) {    return T * ((rand() << 1) - RAND_MAX);}double solve(int id) {    double x = id, now = F(x);    Best = min(Best, now);    for(double T = 101; T > eps; T *= Dlt) {        double wx = x + getrand(T), wv = F(wx);        if(wx > eps && (wx - 100 <= eps)) {            if(wv < Best) x = wx, Best = wv, now = wv;            if(wv < now || ((exp((wv - now) / T)) * RAND_MAX < rand())) now = wv, x = wx;        }    }}int main() {srand((unsigned)time(NULL));    scanf("%d", &T);    while(T--) {                Best = 1e20;        scanf("%lf", &Y);        int times = 100;        while(times--) solve(times);        printf("%.4lf\n", Best);    }        return 0;}/*31002001000000000*/