tsp蛮力法(dfs) | 易学教程

#include <iostream>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <fstream>
#include <iomanip>   // 本文用于输出对齐
using namespace std;
const int max_vexNum = 20;
bool is_visited[max_vexNum];
int path_num = 0;
int bestLength = 10000000;
int path_index = 0;
int path_DFS[max_vexNum][max_vexNum];
double lenth_DFS[max_vexNum];
typedef struct {
   int vex_num, arc_num;           // 顶点数边数
   double arcs[max_vexNum][max_vexNum];   // 邻接矩阵
}Graph;
int _findCityIndex(Graph G, int city_start) {
   for (int i = 0; i < G.vex_num; i++)
   {
       if (i== city_start)
       {
           return i;
       }
   }
   cout << "【error】当前城市未找到！" << endl;
   return -1;
}
void DFS(Graph G, int city_start) {
   int v_index = _findCityIndex(G, city_start);   // 起始城市,每次调用（递归）都更新.

   if (path_index == G.vex_num - 1 && G.arcs[v_index][0] > 0)
   {
       path_DFS[path_num][path_index] = city_start;
       path_DFS[path_num][path_index + 1] = 0; // A为起始城市
       lenth_DFS[path_num] = 0;   // 存储最短路径

       // 计算最短路径
       for (int i = 0; i < G.vex_num; i++)
       {
           lenth_DFS[path_num] += G.arcs[path_DFS[path_num][i] ][path_DFS[path_num][i + 1] ];
       }

       if (bestLength > lenth_DFS[path_num])
       {
           // 更新最短路径
           bestLength = lenth_DFS[path_num];
       }

       cout << "第【" << (path_num + 1) << "】条路径" << endl;
       for (int i = 0; i < G.vex_num; i++)
           cout << path_DFS[path_num][i] << "->";
       cout<<"0"<< endl;
       path_num++;   // 下一条路径
       // 初始化下一次路径与上一次相同
       for (int i = 0; i < G.vex_num; i++)
       {
           path_DFS[path_num][i] = path_DFS[path_num - 1][i];
       }
       return;
   }
   else
   {
       for (int i = 0; i < G.vex_num; i++)
       {
           if (G.arcs[v_index][i] > 0 && !is_visited[i])
           {
               path_DFS[path_num][path_index] = city_start;
               path_index++;
               is_visited[v_index] = true;
               DFS(G, i );
               path_index--;
               is_visited[v_index] = false;
           }
       }
   }

}
int main() {
   Graph G ;
   cout << "tsp问题蛮力法..." << endl;
   cout << "多少个城市:" << endl;
   cin >> G.vex_num;
   cout << "多少条路径" << endl;
   cin >> G.arc_num;
   cout << "路径起点终点，路径长度" << endl;

   for (int i = 0; i < G.arc_num; i++) {
       int a, b, c;
       cin >> a >> b >> c;
       G.arcs[a][b] = c;
       G.arcs[b][a] = c;
       G.arcs[i][i] = 0;
   }

   for (int i = 0; i < G.vex_num; i++)
   {

       for (int j = 0; j< G.vex_num; j++)
           cout << G.arcs[i][j] << " ";
           cout<< endl;
   }
   for (int i = 0; i < G.vex_num; i++)
   {
       is_visited[i] = false;
   }

   cout << "开始城市是-0" << endl;
       int city_start=0;

time_t T_begin = clock();
DFS(G, city_start);

   for (int i = 0; i < path_num; i++)
   {
       for (int j = 0; j <= G.vex_num; j++)
       {
           // cout<<path_DFS[i][j]<<" ";
           // DFS_fout<<path_DFS[i][j]<<" ";
       }
       // cout<<"对应的路程lenth_DFS[] = "<<lenth_DFS[i]<<endl;
       // DFS_fout<<"对应的路程lenth_DFS[] = "<<lenth_DFS[i]<<endl;
   }

// DFS_fout<<"最短路程bestLength = "<<bestLength<<endl;
cout << "最短路程bestLength = " << bestLength << endl;

   time_t T_end = clock();
   double RunningTime = double(T_end - T_begin) / CLOCKS_PER_SEC;
   // DFS_fout<<"程序运行时间 RunningTime = "<<RunningTime<<endl;
   cout << "程序运行时间 RunningTime = " << RunningTime << endl;
   system("pause");
   return 0;
}

来源：CSDN

作者：qq_40533899

链接：https://blog.csdn.net/qq_40533899/article/details/103656768

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