Given a binary tree implemented using an array, find the nearest neighbor to the right of any given node

FindRightNeighborArrayTree.java

public class FindRightNeighborArrayTree {
	
	final Integer[] tree = new Integer[64];
	
	public void insert(int value) {
		if (tree[1] == null) {
			tree[1] = value;
			return;
		}
		
		//set current to root node
		Integer currentLocation = 1;
		Integer currentValue = tree[currentLocation];
		
		while (true) {
			Integer childLocation;
			if (value < currentValue) {
				childLocation = currentLocation * 2;
			} else if (value > currentValue) {
				childLocation = currentLocation * 2 + 1;
			} else {
				//ignore duplicate values
				return;
			}
			
			if (tree[childLocation] == null) {
				tree[childLocation] = value;
				return;
			} else {
				currentValue = tree[childLocation];
				currentLocation = childLocation;
			}
		}
	}
	
	public Integer findValue(int value) {
		return findValue(value, 1);
	}
	
	private Integer findValue(int value, int position) {
		if (tree[position] == null) {
			return null;
		}
		
		if (value < tree[position]) {
			return findValue(value, position * 2);
		} else if (value > tree[position]) {
			return findValue(value, position * 2 + 1);
		} else {
			return position;
		}
	}
	
	public Integer findNeighborToTheRight(int value) {
		int startPosition = findValue(value);
		
		//if start is a power of 2, this is the right most node on this level
		if (isPowerOfTwo(startPosition + 1)) {
			return null;
		}
		
		int current = startPosition + 1;
		while (!isPowerOfTwo(current)) {
			if (tree[current] != null) {
				return tree[current];
			}
			current++;
		}
		return null;
	}
	
	private boolean isPowerOfTwo(int num) {
		return (num & (num - 1)) == 0;
	}
	
	public static void main(String args[]) {
		FindRightNeighborArrayTree tree = new FindRightNeighborArrayTree();
		
		tree.insert(10);
		tree.insert(5);
		tree.insert(3);
		tree.insert(4);
		tree.insert(1);
		tree.insert(2);
		tree.insert(0);
		tree.insert(7);
		tree.insert(8);
		tree.insert(9);
		tree.insert(6);
		tree.insert(15);
		tree.insert(12);
		tree.insert(11);
		tree.insert(13);
		tree.insert(14);
		tree.insert(18);
		tree.insert(16);
		tree.insert(17);
		tree.insert(20);
		tree.insert(19);
		
//                       10
//                      /  \
//                    /      \
//                  /          \
//                /              \
//               5                15
//              / \              /  \
//            /     \          /      \
//           3       7        12       18
//          / \     / \      /  \     /  \
//         1   4   6   8   11    13  16   20
//        / \           \         \   \   /
//       0   2           9        14  17 19
		
		for (int i = 0; i < 21; i++) {
			System.out.println("Node to the right of " + i + " is: " + 
					tree.findNeighborToTheRight(i));
		}
	}
	
}