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

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

@@ -0,0 +1,99 @@
+package com.thealgorithms.searches;
+
+import static java.lang.String.format;
+
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.IntStream;
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+
+/**
+ * The UpperBound method is used to return an index pointing to the first
+ * element in the range [first, last) which has a value greater than val, or the
+ * last index if no such element exists i.e. the index of the next smallest
+ * number just greater than that number. If there are multiple values that are
+ * equal to val it returns the index of the first such value.
+ *
+ * <p>
+ * This is an extension of BinarySearch.
+ *
+ * <p>
+ * Worst-case performance O(log n) Best-case performance O(1) Average
+ * performance O(log n) Worst-case space complexity O(1)
+ *
+ * @author Pratik Padalia (https://github.com/15pratik)
+ * @see SearchAlgorithm
+ * @see BinarySearch
+ */
+class UpperBound implements SearchAlgorithm {
+
+    // Driver Program
+    public static void main(String[] args) {
+        // Just generate data
+        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 for which the upper bound is to be found
+        int val = integers[r.nextInt(size - 1)] + 1;
+
+        UpperBound search = new UpperBound();
+        int atIndex = search.find(integers, val);
+
+        System.out.println(
+                format(
+                        "Val: %d. Upper Bound Found %d at index %d. An array length %d",
+                        val, integers[atIndex], atIndex, size));
+
+        boolean toCheck = integers[atIndex] > val || integers[size - 1] < val;
+        System.out.println(
+                format(
+                        "Upper Bound found at an index: %d. Is greater or max element: %b", atIndex, toCheck));
+    }
+
+    /**
+     * @param array is an array where the UpperBound value is to be found
+     * @param key is an element for which the UpperBound is to be found
+     * @param <T> is any comparable type
+     * @return index of the UpperBound element
+     */
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        return search(array, key, 0, array.length - 1);
+    }
+
+    /**
+     * This method implements the Generic Binary Search
+     *
+     * @param array The array to make the binary search
+     * @param key The number you are looking for
+     * @param left The lower bound
+     * @param right The upper bound
+     * @return the location of the key
+     */
+    private <T extends Comparable<T>> int search(T[] array, T key, int left, int right) {
+        if (right <= left) {
+            return left;
+        }
+
+        // find median
+        int median = (left + right) >>> 1;
+        int comp = key.compareTo(array[median]);
+
+        if (comp < 0) {
+            // key is smaller, median position can be a possible solution
+            return search(array, key, left, median);
+        } else {
+            // key we are looking is greater, so we must look on the right of median position
+            return search(array, key, median + 1, right);
+        }
+    }
+}