贪婪算法求解TSP问题：

贪婪算法求解TSP问题：

贪婪算法（greedy algorithm）

贪心法，又称贪心算法、贪婪算法、或称贪婪法，是一种在每一步选择中都采取在当前状态下最好或最优（即最有利）的选择，从而希望导致结果是最好或最优的算法。
贪心算法在有最优子结构的问题中尤为有效。最优子结构的意思是局部最优解能决定全局最优解。简单地说，问题能够分解成子问题来解决，子问题的最优解能递推到最终问题的最优解。

TSP问题

旅行推销员问题（英语：Travelling salesman problem, TSP）是这样一个问题：给定一系列城市和每对城市之间的距离，求解访问每一座城市一次并回到起始城市的最短回路。它是组合优化中的一个NP困难问题，在运筹学和理论计算机科学中非常重要。

• 为了简化问题，这里使用数字来代替各点
• A——1
• B——2
• C——3
• D——4
• E——5

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代码块

#include <iostream>using namespace std;#define n 5int main(){    int dis[n][n];    int i;    //int k = 1;    int index = 1;    int l = 1;    int max = 1000;    int disSum = 0;    int flag = 0;    int c[n];    int N = 4;     c[0] = 0;    dis[0][1] = 2; dis[0][2] = 10; dis[0][3] = 5; dis[0][4] = 1;    dis[1][0] = 2; dis[1][2] = 7; dis[1][3] = 8; dis[1][4] = 4;    dis[2][0] = 10; dis[2][1] = 7; dis[2][3] = 3; dis[2][4] = 6;    dis[3][0] = 5; dis[3][1] = 8; dis[3][2] = 3; dis[3][4] = 9;    dis[4][0] = 1; dis[4][1] = 4;dis[4][2] = 6; dis[4][3] = 9;    while(index < n)    {         int k = 1;        while(k < n && N >=0)        {            i = 0;            while(i < l)            {                if(k == c[i])                  {                       k = k+1;                      flag = 1;                      i = 0;                  }                else                  {                       i = i+1;                        flag = 0;                         }            }              if(flag == 0 && dis[c[index-1]][k] < max )              {                max = dis[c[index-1]][k];                c[index] = k;                k = k+1;                l = index+1;            }             else// if(flag == 1 || dis[c[index-1]][k] > max)            {                 k = k+1;            }            }            cout << "the distance between "<< c[index-1] << " and  " << c[index] << " is " << max << "\n";      disSum = disSum + max;        index = index + 1;    //k = 1;    max = 1000;    N = N-1;    }        cout << "the first city is " << c[0] << "\n";     for(int x = 1; x < n; x++)    {        printf("the next city is %d \n",c[x]);//cout << c[x] << " ";    }    cout << "the shortest diastance is " << disSum << "\n" ;    system("pause");    }