Feature/adding the travelling salesman problem

src/main/java/com/thealgorithms/greedyalgorithms/TravellingSalesmanProblem.java

@@ -0,0 +1,154 @@
+import java.util.*;
+class TSP{
+
+static int V = 4;
+
+// 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, 10, 15, 20},
+                   {10, 0, 35, 25},
+                   {15, 35, 0, 30},
+                   {20, 25, 30, 0}};
+  int s = 0;
+  System.out.println(
+  travllingSalesmanProblem(graph, s));
+}
+}

src/main/java/com/thealgorithms/searches/BinarySearch.java

@@ -1,33 +1,27 @@
-package com.thealgorithms.searches;
-
-import com.thealgorithms.devutils.searches.SearchAlgorithm;
 import java.util.Arrays;
 import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.stream.IntStream;
 
 /**
- * Binary search is one of the most popular algorithms The algorithm finds the
- * position of a target value within a sorted array
+ * Binary search is one of the most popular algorithms. 
+ * The algorithm finds the position of a target value within a sorted array.
  *
  * <p>
- * Worst-case performance O(log n) Best-case performance O(1) Average
- * performance O(log n) Worst-case space complexity O(1)
+ * Worst-case performance O(log n) Best-case performance O(1) 
+ * Average performance O(log n) Worst-case space complexity O(1)
  *
  * @author Varun Upadhyay (https://github.com/varunu28)
  * @author Podshivalov Nikita (https://github.com/nikitap492)
- * @see SearchAlgorithm
- * @see IterativeBinarySearch
  */
-class BinarySearch implements SearchAlgorithm {
+public class BinarySearch {
 
     /**
      * @param array is an array where the element should be found
      * @param key is an element which should be found
      * @param <T> is any comparable type
      * @return index of the element
      */
-    @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
         return search(array, key, 0, array.length - 1);
     }
@@ -43,8 +37,9 @@ public <T extends Comparable<T>> int find(T[] array, T key) {
      */
     private <T extends Comparable<T>> int search(T[] array, T key, int left, int right) {
         if (right < left) {
-            return -1; // this means that the key not found
+            return -1; // this means that the key was not found
         }
+
         // find median
         int median = (left + right) >>> 1;
         int comp = key.compareTo(array[median]);
@@ -66,17 +61,33 @@ public static void main(String[] args) {
         int size = 100;
         int maxElement = 100000;
 
-        Integer[] integers = IntStream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().boxed().toArray(Integer[] ::new);
+        Integer[] integers = IntStream
+            .generate(() -> r.nextInt(maxElement))
+            .limit(size)
+            .sorted()
+            .boxed()
+            .toArray(Integer[]::new);
 
         // The element that should be found
         int shouldBeFound = integers[r.nextInt(size - 1)];
 
         BinarySearch search = new BinarySearch();
         int atIndex = search.find(integers, shouldBeFound);
 
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
+        System.out.printf(
+            "Should be found: %d. Found %d at index %d. Array length %d%n",
+            shouldBeFound,
+            integers[atIndex],
+            atIndex,
+            size
+        );
 
         int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
+        System.out.printf(
+            "Found by system method at an index: %d. Is equal: %b%n",
+            toCheck,
+            toCheck == atIndex
+        );
     }
 }
+