slight improvements (williamfiset#152)

* remove unnesessary variable

f is never used and can be deleted safely

* remove unnecessary variable

Variable "in" defined in the scope of the loop is never used and can be safely deleted

* static use of Method/Class

InterpolationSearch is declared static, no need to instantiate

Author: EAlexa

src/main/java/com/williamfiset/algorithms/ai/GeneticAlgorithm_knapsack_01.java

@@ -63,7 +63,6 @@ static long run(int capacity, int[] weights, int[] values) {
       // Setup selection roulette
       for (int i = 1; i <= P; i++) {
 
-        Individual in = generation[i];
         double norm = fitness[i] / fitnessSum;
 
         lo[i] = hi[i - 1] = lo[i - 1] + norm;

src/main/java/com/williamfiset/algorithms/graphtheory/AStar_GridHeuristic.java

@@ -96,8 +96,7 @@ public static double astar(
 
           double g = node.g + edge.cost;
           double h = heuristic(X, Y, edge.to, end);
-          double f = g + h;
-
+          
           if (g < G[edge.to] || !openSet.contains(edge.to)) {
 
             G[edge.to] = g;

src/test/java/com/williamfiset/algorithms/search/InterpolationSearchTest.java

@@ -5,37 +5,32 @@
 import org.junit.Test;
 
 public class InterpolationSearchTest {
-  private static InterpolationSearch search;
-
-  public static void prepareTest() {
-    search = new InterpolationSearch();
-  }
-
+  
   @Test
   public void testCoverage1() {
     int[] arr = {0, 1, 2, 3, 4, 5};
-    int index = search.interpolationSearch(arr, 2);
+    int index = InterpolationSearch.interpolationSearch(arr, 2);
     assertTrue(index == 2);
   }
 
   @Test
   public void testCoverage2() {
     int[] arr = {0, 1, 2, 3, 4, 5};
-    int index = search.interpolationSearch(arr, 5);
+    int index = InterpolationSearch.interpolationSearch(arr, 5);
     assertTrue(index == 5);
   }
 
   @Test
   public void testCoverage3() {
     int[] arr = {0, 1, 2, 3, 4, 5};
-    int index = search.interpolationSearch(arr, -1);
+    int index = InterpolationSearch.interpolationSearch(arr, -1);
     assertTrue(index == -1);
   }
 
   @Test
   public void testCoverage4() {
     int[] arr = {0, 1, 2, 3, 4, 5};
-    int index = search.interpolationSearch(arr, 8);
+    int index = InterpolationSearch.interpolationSearch(arr, 8);
     assertTrue(index == -1);
   }
 }