ADDED TWO DATA STRUCTURE ARRAY ALGORITHMS

src/main/java/com/thealgorithms/datastructures/arrays/LeadersInArray.java

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+package com.thealgorithms.datastructures.arrays;
+
+/**
+ * A utility class to find leaders in an array.
+ *
+ * <p>
+ * A leader is an element greater than all elements to its right.
+ * The rightmost element is always a leader.
+ *
+ * Time Complexity: O(n)
+ * Space Complexity: O(1)
+ *
+ * Author: https://github.com/VeeruYadav45
+ */
+public final class LeadersInArray {
+
+    // Private constructor to prevent instantiation
+    private LeadersInArray() {
+    }
+
+    /**
+     * Prints all leader elements in the array.
+     *
+     * @param arr the input array
+     */
+    public static void findLeaders(final int[] arr) {
+        int n = arr.length;
+        int maxFromRight = arr[n - 1];
+        System.out.print("Leaders: " + maxFromRight + " ");
+
+        for (int i = n - 2; i >= 0; i--) {
+            if (arr[i] > maxFromRight) {
+                maxFromRight = arr[i];
+                System.out.print(maxFromRight + " ");
+            }
+        }
+        System.out.println();
+    }
+
+    /**
+     * Example usage.
+     *
+     * @param args command line arguments (not used)
+     */
+    @SuppressWarnings("PMD.UselessMainMethod")
+    public static void main(final String[] args) {
+        int[] arr = {16, 17, 4, 3, 5, 2};
+        findLeaders(arr);
+    }
+}

src/main/java/com/thealgorithms/datastructures/arrays/PeakElement.java

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+package com.thealgorithms.datastructures.arrays;
+
+/**
+ * A utility class to find a peak element in an array.
+ *
+ * <p>
+ * A peak element is an element greater than or equal to its neighbors.
+ *
+ * Time Complexity: O(log n) using binary search
+ * Space Complexity: O(1)
+ *
+ * Author: https://github.com/VeeruYadav45
+ */
+public final class PeakElement {
+
+    // Private constructor to prevent instantiation
+    private PeakElement() {
+    }
+
+    /**
+     * Finds the index of a peak element using binary search.
+     *
+     * @param arr the input array
+     * @return the index of a peak element
+     */
+    public static int findPeakElement(final int[] arr) {
+        int n = arr.length;
+        int low = 0;
+        int high = n - 1;
+
+        while (low <= high) {
+            int mid = low + (high - low) / 2;
+
+            boolean leftOk = (mid == 0) || (arr[mid] >= arr[mid - 1]);
+            boolean rightOk = (mid == n - 1) || (arr[mid] >= arr[mid + 1]);
+
+            if (leftOk && rightOk) {
+                return mid;
+            }
+
+            if (mid > 0 && arr[mid - 1] > arr[mid]) {
+                high = mid - 1;
+            } else {
+                low = mid + 1;
+            }
+        }
+
+        return -1;
+    }
+
+    /**
+     * Example usage.
+     *
+     * @param args command line arguments (not used)
+     */
+    @SuppressWarnings("PMD.UselessMainMethod")
+    public static void main(final String[] args) {
+        int[] arr = {1, 3, 20, 4, 1, 0};
+        int peakIndex = findPeakElement(arr);
+        System.out.println("Peak element is " + arr[peakIndex]);
+    }
+}