Add tests, remove main, improve docs in ExponentialSearch (#5664)

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

@@ -2,44 +2,47 @@ 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;
 
+/**
+ * ExponentialSearch is an algorithm that efficiently finds the position of a target
+ * value within a sorted array. It works by expanding the range to find the bounds
+ * where the target might exist and then using binary search within that range.
+ *
+ * <p>
+ * Worst-case time complexity: O(log n)
+ * Best-case time complexity: O(1) when the element is found at the first position.
+ * Average time complexity: O(log n)
+ * Worst-case space complexity: O(1)
+ * </p>
+ *
+ * <p>
+ * Note: This algorithm requires that the input array be sorted.
+ * </p>
+ */
 class ExponentialSearch implements SearchAlgorithm {
 
-    public static void main(String[] args) {
-        Random r = ThreadLocalRandom.current();
-
-        int size = 100;
-        int maxElement = 100000;
-
-        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)];
-
-        ExponentialSearch search = new ExponentialSearch();
-        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);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
-
+    /**
+     * Finds the index of the specified key in a sorted array using exponential search.
+     *
+     * @param array The sorted array to search.
+     * @param key The element to search for.
+     * @param <T> The type of the elements in the array, which must be comparable.
+     * @return The index of the key if found, otherwise -1.
+     */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T key) {
-        if (array[0] == key) {
+        if (array.length == 0) {
+            return -1;
+        }
+        if (array[0].equals(key)) {
             return 0;
         }
-        if (array[array.length - 1] == key) {
-            return array.length;
+        if (array[array.length - 1].equals(key)) {
+            return array.length - 1;
         }
 
         int range = 1;
-
-        while (range < array.length && array[range].compareTo(key) <= -1) {
+        while (range < array.length && array[range].compareTo(key) < 0) {
             range = range * 2;
         }