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

src/main/java/com/thealgorithms/maths/FindMaxRecursion.java

@@ -0,0 +1,55 @@
+package com.thealgorithms.maths;
+
+import java.util.Arrays;
+import java.util.Random;
+
+public class FindMaxRecursion {
+
+    public static void main(String[] args) {
+        Random rand = new Random();
+
+        /* rand size */
+        int size = rand.nextInt(100) + 1;
+        int[] array = new int[size];
+
+        /* init array with rand numbers */
+        for (int i = 0; i < size; i++) {
+            array[i] = rand.nextInt() % 100;
+        }
+
+        assert max(array, array.length) == Arrays.stream(array).max().getAsInt();
+        assert max(array, 0, array.length - 1) == Arrays.stream(array).max().getAsInt();
+    }
+
+    /**
+     * Get max of array using divide and conquer algorithm
+     *
+     * @param array contains elements
+     * @param low the index of the first element
+     * @param high the index of the last element
+     * @return max of {@code array}
+     */
+    public static int max(int[] array, int low, int high) {
+        if (low == high) {
+            return array[low]; // or array[high]
+        }
+
+        int mid = (low + high) >>> 1;
+
+        int leftMax = max(array, low, mid); // get max in [low, mid]
+        int rightMax = max(array, mid + 1, high); // get max in [mid+1, high]
+
+        return Math.max(leftMax, rightMax);
+    }
+
+    /**
+     * Get max of array using recursion algorithm
+     *
+     * @param array contains elements
+     * @param len length of given array
+     * @return max value of {@code array}
+     */
+    public static int max(int[] array, int len) {
+        return len == 1 ? array[0] : Math.max(max(array, len - 1), array[len - 1]);
+    }
+}