HDU 2899Strange fuction(模拟退火)

题意

题目链接

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<iostream>

#include<cstdio>

#include<cmath>

#include<cstdlib>

#include<ctime>

using namespace std;

const int MAXN = 1e6 + ;

const double eps = 1e-, Dlt = 0.98;

int T;

double Y, Best;

double F(double x) {

    return  * x * x * x * x * x * x  * x +  * x * x * x * x * x * x +  * x * x * x +  * x * x - Y * x;

}

double getrand(double T) {

    return T * ((rand() << ) - RAND_MAX);

}

double solve(int id) {

    double x = id, now = F(x);

    Best = min(Best, now);

    for(double T = ; T > eps; T *= Dlt) {

        double wx = x + getrand(T), wv = F(wx);

        if(wx > eps && (wx -  <= 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 = ;

        while(times--) solve(times);

        printf("%.4lf\n", Best);

    }

    return ;

}

/*

3

100

200

1000000000

*/