#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
#include <stdio.h>
#include <time.h>
#include <math.h>
#define N 30 //城市数量
#define T 3000 //初始温度
#define EPS 1e-8 //终止温度
#define DELTA 0.98 //温度衰减率
#define LIMIT 1000 //概率选择上限
#define OLOOP 20 //外循环次数
#define ILOOP 100 //内循环次数
using namespace std;
//定义路线结构体
struct Path
{
int citys[N];
double len;
};
//定义城市点坐标
struct Point
{
double x, y;
};
Path bestPath; //记录最优路径
Point p[N]; //每个城市的坐标
double w[N][N]; //两两城市之间路径长度
int nCase; //测试次数
double dist(Point A, Point B)
{
return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));
}
void GetDist(Point p[], int n)
{
for(int i = 0; i < n; i++)
for(int j = i + 1; j < n; j++)
w[i][j] = w[j][i] = dist(p[i], p[j]);
}
void Input(Point p[], int &n)
{
scanf("%d", &n);
for(int i = 0; i < n; i++)
scanf("%lf %lf", &p[i].x, &p[i].y);
}
void Init(int n)
{
nCase = 0;
bestPath.len = 0;
for(int i = 0; i < n; i++)
{
bestPath.citys[i] = i;
if(i != n - 1)
{
printf("%d--->", i);
bestPath.len += w[i][i + 1];
}
else
printf("%d\n", i);
}
printf("\nInit path length is : %.3lf\n", bestPath.len);
printf("-----------------------------------\n\n");
}
void Print(Path t, int n)
{
printf("Path is : ");
for(int i = 0; i < n; i++)
{
if(i != n - 1)
printf("%d-->", t.citys[i]);
else
printf("%d\n", t.citys[i]);
}
printf("\nThe path length is : %.3lf\n", t.len);
printf("-----------------------------------\n\n");
}
Path GetNext(Path p, int n)
{
Path ans = p;
int x = (int)(n * (rand() / (RAND_MAX + 1.0)));
int y = (int)(n * (rand() / (RAND_MAX + 1.0)));
while(x == y)
{
x = (int)(n * (rand() / (RAND_MAX + 1.0)));
y = (int)(n * (rand() / (RAND_MAX + 1.0)));
}
swap(ans.citys[x], ans.citys[y]);
ans.len = 0;
for(int i = 0; i < n - 1; i++)
ans.len += w[ans.citys[i]][ans.citys[i + 1]];
cout << "nCase = " << nCase << endl;
Print(ans, n);
nCase++;
return ans;
}
void SA(int n)
{
double t = T;
srand((unsigned)(time(NULL)));
Path curPath = bestPath;
Path newPath = bestPath;
int P_L = 0;
int P_F = 0;
while(1) //外循环,主要更新参数t,模拟退火过程
{
for(int i = 0; i < ILOOP; i++) //内循环,寻找在一定温度下的最优值
{
newPath = GetNext(curPath, n);
double dE = newPath.len - curPath.len;
if(dE < 0) //如果找到更优值,直接更新
{
curPath = newPath;
P_L = 0;
P_F = 0;
}
else
{
double rd = rand() / (RAND_MAX + 1.0);
//如果找到比当前更差的解,以一定概率接受该解,并且这个概率会越来越小
if(exp(dE / t) > rd && exp(dE / t) < 1)
curPath = newPath;
P_L++;
}
if(P_L > LIMIT)
{
P_F++;
break;
}
}
if(curPath.len < bestPath.len)
bestPath = curPath;
if(P_F > OLOOP || t < EPS)
break;
t *= DELTA;
}
}
int main(int argc, const char * argv[]) {
freopen("TSP.data", "r", stdin);
int n;
Input(p, n);
GetDist(p, n);
Init(n);
SA(n);
Print(bestPath, n);
printf("Total test times is : %d\n", nCase);
return 0;
}
来源https://www.cnblogs.com/ranjiewen/p/6084052.html
可以跑大数组,但是解决的TSP问题没有回到原点,请问怎么修改才能回到原点?