Change project structure to a Maven Java project + Refactor (#2816)

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

@@ -0,0 +1,81 @@
+package com.thealgorithms.searches;
+
+import static java.lang.String.format;
+
+import java.util.Arrays;
+import java.util.Random;
+import java.util.stream.Stream;
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+
+/**
+ * A iterative version of a ternary search algorithm This is better way to
+ * implement the ternary search, because a recursive version adds some overhead
+ * to a stack. But in java the compile can transform the recursive version to
+ * iterative implicitly, so there are no much differences between these two
+ * algorithms
+ *
+ * <p>
+ * Worst-case performance Θ(log3(N)) Best-case performance O(1) Average
+ * performance Θ(log3(N)) Worst-case space complexity O(1)
+ *
+ * @author Podshivalov Nikita (https://github.com/nikitap492)
+ * @see SearchAlgorithm
+ * @see TernarySearch
+ * @since 2018-04-13
+ */
+public class IterativeTernarySearch implements SearchAlgorithm {
+
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        int left = 0;
+        int right = array.length - 1;
+
+        while (right > left) {
+
+            int leftCmp = array[left].compareTo(key);
+            int rightCmp = array[right].compareTo(key);
+            if (leftCmp == 0) {
+                return left;
+            }
+            if (rightCmp == 0) {
+                return right;
+            }
+
+            int leftThird = left + (right - left) / 3 + 1;
+            int rightThird = right - (right - left) / 3 - 1;
+
+            if (array[leftThird].compareTo(key) <= 0) {
+                left = leftThird;
+            } else {
+                right = rightThird;
+            }
+        }
+
+        return -1;
+    }
+
+    public static void main(String[] args) {
+        // just generate data
+        Random r = new Random();
+        int size = 100;
+        int maxElement = 100000;
+        Integer[] integers
+                = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[]::new);
+
+        // the element that should be found
+        Integer shouldBeFound = integers[r.nextInt(size - 1)];
+
+        IterativeTernarySearch search = new IterativeTernarySearch();
+        int atIndex = search.find(integers, shouldBeFound);
+
+        System.out.println(
+                format(
+                        "Should be found: %d. Found %d at index %d. An array length %d",
+                        shouldBeFound, integers[atIndex], atIndex, size));
+
+        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
+        System.out.println(
+                format(
+                        "Found by system method at an index: %d. Is equal: %b", toCheck, toCheck == atIndex));
+    }
+}