Merge pull request #370 from RAJCHAKRABORTY3416/patch-1

Create Travelling Salesman Problem.java

Travelling Salesman Problem.java

@@ -0,0 +1,72 @@
+// Java implementation of the approach
+class GFG 
+{
+
+	// Function to find the minimum weight 
+	// Hamiltonian Cycle
+	static int tsp(int[][] graph, boolean[] v, 
+				int currPos, int n, 
+				int count, int cost, int ans) 
+	{
+
+		// If last node is reached and it has a link
+		// to the starting node i.e the source then
+		// keep the minimum value out of the total cost
+		// of traversal and "ans"
+		// Finally return to check for more possible values
+		if (count == n && graph[currPos][0] > 0) 
+		{
+			ans = Math.min(ans, cost + graph[currPos][0]);
+			return ans;
+		}
+
+		// BACKTRACKING STEP
+		// Loop to traverse the adjacency list
+		// of currPos node and increasing the count
+		// by 1 and cost by graph[currPos,i] value
+		for (int i = 0; i < n; i++) 
+		{
+			if (v[i] == false && graph[currPos][i] > 0) 
+			{
+
+				// Mark as visited
+				v[i] = true;
+				ans = tsp(graph, v, i, n, count + 1,
+						cost + graph[currPos][i], ans);
+
+				// Mark ith node as unvisited
+				v[i] = false;
+			}
+		}
+		return ans;
+	}
+
+	// Driver code
+	public static void main(String[] args)
+	{
+
+		// n is the number of nodes i.e. V
+		int n = 4;
+
+		int[][] graph = {{0, 10, 15, 20},
+						{10, 0, 35, 25},
+						{15, 35, 0, 30},
+						{20, 25, 30, 0}};
+
+		// Boolean array to check if a node
+		// has been visited or not
+		boolean[] v = new boolean[n];
+
+		// Mark 0th node as visited
+		v[0] = true;
+		int ans = Integer.MAX_VALUE;
+
+		// Find the minimum weight Hamiltonian Cycle
+		ans = tsp(graph, v, 0, n, 1, 0, ans);
+
+		// ans is the minimum weight Hamiltonian Cycle
+		System.out.println(ans);
+	}
+}
+
+// This code is contributed by Raj Chakraborty