Added solution to Travelling Salesmen Problem

Contributors.html

@@ -1956,6 +1956,11 @@
           "id":357,
           "fullname": "Nabeel Hussain M N",
           "username": "https://github.com/nabeel001"
+        },
+        {
+          "id":358,
+          "fullname": "Avadhoot Kulkarni",
+          "username": "https://github.com/AvadhootK"
         }
     ];
 

Program's_Contributed_By_Contributors/C++/TSP.cpp

@@ -0,0 +1,124 @@
+// Travelling salesman problem solution
+#include <iostream>
+#include <string>
+#include <vector>
+using namespace std;
+
+class Graph
+{
+    int **matrix;
+    int stpt, endpt, cost;
+
+public:
+    int r, c;
+    vector<int> cost_vector; // to store costs
+    void get_matrix()
+    {
+        cout << "No.of rows ";
+        cin >> r;
+        cout << "No.of columns ";
+        cin >> c;
+    }
+    void set_matrix()
+    {
+        matrix = new int *[r];
+        for (int i = 0; i < r; i++)
+        {
+            matrix[i] = new int[c];
+        }
+        for (int i = 0; i < r; i++)
+        {
+            for (int j = 0; j < c; j++)
+            {
+                matrix[i][j] = 0;
+            }
+        }
+    }
+    void get_data()
+    {
+        cout << "Starting point ";
+        cin >> stpt;
+        cout << "Ending point ";
+        cin >> endpt;
+        cout << "Cost ";
+        cin >> cost;
+        matrix[stpt][endpt] = cost;
+    }
+    void put_data()
+    {
+        for (int i = 0; i < r; i++)
+        {
+            for (int j = 0; j < c; j++)
+            {
+                cout << matrix[i][j] << " ";
+            }
+            cout << endl;
+        }
+    }
+    void nearest_neighbor(int city)
+    {
+        // parameter is source city
+        int *visited = new int[r]{0};
+        // int visited[3] = {0};
+        int value = 1e5;
+        int j, index, cost = 0, k = city, flag = 0; // flag - to check if all cities are visited
+        string s = to_string(city + 1);             // to store paths
+        // for cities
+        // k-rows , j-columns
+        while (visited[city] < 2)
+        {
+            visited[k]++;
+            flag++;
+            for (j = 0; j < r; j++)
+            {
+                if (k != j && visited[j] == 0 && matrix[k][j] < value)
+                {
+                    value = matrix[k][j];
+                    index = j;
+                }
+                // if all cities are visited once
+                else if (flag == r)
+                {
+                    value = matrix[k][0];
+                    index = city;
+                    visited[index]++;
+                }
+            }
+            cost = cost + matrix[k][index];
+            k = index;
+            s.append(" -> " + to_string(k + 1));
+            value = 1e5;
+        }
+        cout << "Path -> " << s << "   :   Cost = " << cost << endl;
+        cost_vector.push_back(cost);
+    }
+};
+
+int main()
+{
+    Graph g;
+    char c;
+    int smallest;
+    g.get_matrix();
+    g.set_matrix();
+    do
+    {
+        g.get_data();
+        cout << "Do you want to continue? y/n ";
+        cin >> c;
+    } while (c == 'y');
+    g.put_data();
+    for (int i = 0; i < g.r; i++)
+    {
+        g.nearest_neighbor(i);
+    }
+    smallest = g.cost_vector.front();
+    for (int i = 0; i < g.cost_vector.size(); i++)
+    {
+        if (g.cost_vector[i] < smallest)
+        {
+            smallest = g.cost_vector[i];
+        }
+    }
+    cout << "Optimal cost : " << smallest;
+}