I got Travelling Salesman Problem code from geeksforgeeks website ( https://www.geeksforgeeks.org/traveling-salesman-problem-tsp-implementation/ ) and try to implemented on 26 different city, but when I run the code it takes forever to show the result. here is my code:
import java.util.ArrayList;
public class SPE {
static int V = 26;
// implementation of traveling
// Salesman Problem
static int travllingSalesmanProblem(int graph[][],
int s) {
// store all vertex apart
// from source vertex
ArrayList<Integer> vertex = new ArrayList<Integer>();
for (int i = 0; i < V; i++)
if (i != s)
vertex.add(i);
// store minimum weight
// Hamiltonian Cycle.
int min_path = Integer.MAX_VALUE;
do {
// store current Path weight(cost)
int current_pathweight = 0;
// compute current path weight
int k = s;
for (int i = 0; i < vertex.size(); i++) {
current_pathweight += graph[k][vertex.get(i)];
k = vertex.get(i);
}
current_pathweight += graph[k][s];
// update minimum
min_path = Math.min(min_path,
current_pathweight);
} while (findNextPermutation(vertex));
return min_path;
}
// Function to swap the data
// present in the left and right indices
public static ArrayList<Integer> swap(
ArrayList<Integer> data,
int left, int right) {
// Swap the data
int temp = data.get(left);
data.set(left, data.get(right));
data.set(right, temp);
// Return the updated array
return data;
}
// Function to reverse the sub-array
// starting from left to the right
// both inclusive
public static ArrayList<Integer> reverse(
ArrayList<Integer> data,
int left, int right) {
// Reverse the sub-array
while (left < right) {
int temp = data.get(left);
data.set(left++,
data.get(right));
data.set(right--, temp);
}
// Return the updated array
return data;
}
// Function to find the next permutation
// of the given integer array
public static boolean findNextPermutation(
ArrayList<Integer> data) {
// If the given dataset is empty
// or contains only one element
// next_permutation is not possible
if (data.size() <= 1)
return false;
int last = data.size() - 2;
// find the longest non-increasing
// suffix and find the pivot
while (last >= 0) {
if (data.get(last) < data.get(last + 1)) {
break;
}
last--;
}
// If there is no increasing pair
// there is no higher order permutation
if (last < 0)
return false;
int nextGreater = data.size() - 1;
// Find the rightmost successor
// to the pivot
for (int i = data.size() - 1; i > last; i--) {
if (data.get(i) > data.get(last)) {
nextGreater = i;
break;
}
}
// Swap the successor and
// the pivot
data = swap(data,
nextGreater, last);
// Reverse the suffix
data = reverse(data, last + 1,
data.size() - 1);
// Return true as the
// next_permutation is done
return true;
}
// Driver Code
public static void main(String args[]) {
// matrix representation of graph
int graph[][] = {
{ 0, 83, 93, 129, 133, 139, 151, 169, 135, 114, 110, 98, 99, 95, 81, 152, 159, 181, 172,
185, 147, 157, 185, 220, 127, 181 },
{ 83, 0, 40, 53, 62, 64, 91, 116, 93, 84, 95, 98, 89, 68, 67, 127, 156, 175, 152, 165,
160, 180, 223, 268, 179, 197 },
{ 93, 40, 0, 42, 42, 49, 59, 81, 54, 44, 58, 64, 54, 31, 36, 86, 117, 135, 112, 125,
124, 147, 193, 241, 157, 161 },
{ 129, 53, 42, 0, 11, 11, 46, 72, 65, 70, 88, 100, 89, 66, 76, 102, 142, 156, 127, 139,
155, 180, 228, 278, 197, 190 },
{ 133, 62, 42, 11, 0, 9, 35, 61, 55, 62, 82, 95, 84, 62, 74, 93, 133, 146, 117, 128,
148, 173, 222, 272, 194, 182 },
{ 139, 64, 49, 11, 9, 0, 39, 65, 63, 71, 90, 103, 92, 71, 82, 100, 141, 153, 124, 135,
156, 181, 230, 280, 202, 190 },
{ 151, 91, 59, 46, 35, 39, 0, 26, 34, 52, 71, 88, 77, 63, 78, 66, 110, 119, 88, 98, 130,
156, 206, 257, 188, 160 },
{ 169, 116, 81, 72, 61, 65, 26, 0, 37, 59, 75, 92, 83, 76, 91, 54, 98, 103, 70, 78, 122,
148, 198, 250, 188, 148 },
{ 135, 93, 54, 65, 55, 63, 34, 37, 0, 22, 39, 56, 47, 40, 55, 37, 78, 91, 62, 74, 96,
122, 172, 223, 155, 128 },
{ 114, 84, 44, 70, 62, 71, 52, 59, 22, 0, 20, 36, 26, 20, 34, 43, 74, 91, 68, 82, 86,
111, 160, 210, 136, 121 },
{ 110, 95, 58, 88, 82, 90, 71, 75, 39, 20, 0, 18, 11, 27, 32, 42, 61, 80, 64, 77, 68,
92, 140, 190, 116, 103 },
{ 98, 98, 64, 100, 95, 103, 88, 92, 56, 36, 18, 0, 11, 34, 31, 56, 63, 85, 75, 87, 62,
83, 129, 178, 100, 99 },
{ 99, 89, 54, 89, 84, 92, 77, 83, 47, 26, 11, 11, 0, 23, 24, 53, 68, 89, 74, 87, 71, 93,
140, 189, 111, 107 },
{ 95, 68, 31, 66, 62, 71, 63, 76, 40, 20, 27, 34, 23, 0, 15, 62, 87, 106, 87, 100, 93,
116, 163, 212, 132, 130 },
{ 81, 67, 36, 76, 74, 82, 78, 91, 55, 34, 32, 31, 24, 15, 0, 73, 92, 112, 96, 109, 93,
113, 158, 205, 122, 130 },
{ 152, 127, 86, 102, 93, 100, 66, 54, 37, 43, 42, 56, 53, 62, 73, 0, 44, 54, 26, 39, 68,
94, 144, 196, 139, 95 },
{ 159, 156, 117, 142, 133, 141, 110, 98, 78, 74, 61, 63, 68, 87, 92, 44, 0, 22, 34, 38,
30, 53, 102, 154, 109, 51 },
{ 181, 175, 135, 156, 146, 153, 119, 103, 91, 91, 80, 85, 89, 106, 112, 54, 22, 0, 33,
29, 46, 64, 107, 157, 125, 51 },
{ 172, 152, 112, 127, 117, 124, 88, 70, 62, 68, 64, 75, 74, 87, 96, 26, 34, 33, 0, 13,
63, 87, 135, 186, 141, 81 },
{ 185, 165, 125, 139, 128, 135, 98, 78, 74, 82, 77, 87, 87, 100, 109, 39, 38, 29, 13, 0,
68, 90, 136, 186, 148, 79 },
{ 147, 160, 124, 155, 148, 156, 130, 122, 96, 86, 68, 62, 71, 93, 93, 68, 30, 46, 63,
68, 0, 26, 77, 128, 80, 37 },
{ 157, 180, 147, 180, 173, 181, 156, 148, 122, 111, 92, 83, 93, 116, 113, 94, 53, 64,
87, 90, 26, 0, 50, 102, 65, 27 },
{ 185, 223, 193, 228, 222, 230, 206, 198, 172, 160, 140, 129, 140, 163, 158, 144, 102,
107, 135, 136, 77, 50, 0, 51, 64, 58 },
{ 220, 268, 241, 278, 272, 280, 257, 250, 223, 210, 190, 178, 189, 212, 205, 196, 154,
157, 186, 186, 128, 102, 51, 0, 93, 10 },
{ 127, 179, 157, 197, 194, 202, 188, 188, 155, 136, 116, 100, 111, 132, 122, 139, 109,
125, 141, 148, 80, 65, 64, 93, 0, 90 },
{ 181, 197, 161, 190, 182, 190, 160, 148, 128, 121, 103, 99, 107, 130, 130, 95, 51, 51,
81, 79, 37, 27, 58, 107, 90, 0 }
};
int s = 0;
System.out.println(
travllingSalesmanProblem(graph, s));
}
}
Can anyone help me with this issue :(
I tried to run the code to almost 3 hours and it didn't show the result.
