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MaxOfATree.java
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MaxOfATree.java
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// Find the maximum in a binary tree
import java.util.Stack;
public class MaxOfATree extends BinaryTree{
// Recursively
public int maxOfBST(BinaryTreeNode root) {
int maxValue = Integer.MIN_VALUE;
if(root != null) {
int leftMax = maxOfBST(root.left);
int rightMax = maxOfBST(root.right);
if(leftMax > rightMax)
maxValue = leftMax;
else if(leftMax < rightMax)
maxValue = rightMax;
if(root.value > maxValue)
maxValue = root.value;
}
return maxValue;
}
// Iterative
public int maxOfBSTItr(BinaryTreeNode root) {
if(root == null)
return -1;
Stack<BinaryTreeNode> stackOne = new Stack<>();
Stack<BinaryTreeNode> stackTwo = new Stack<>();
BinaryTreeNode current = root;
stackOne.push(current);
while(!stackOne.isEmpty()) {
current = stackOne.pop();
stackTwo.push(current);
if(current.left != null)
stackOne.push(current.left);
if(current.right != null)
stackOne.push(current.right);
}
int max = stackTwo.pop().value;
while(!stackTwo.isEmpty()) {
current = stackTwo.pop();
if(max < current.value)
max = current.value;
}
return max;
}
public static void main(String[] args) {
MaxOfATree maxOfATree = new MaxOfATree();
maxOfATree.setRoot(new BinaryTreeNode(1));
System.out.println(maxOfATree.maxOfBST(maxOfATree.treeExample()));
System.out.println(maxOfATree.maxOfBSTItr(maxOfATree.treeExample1()));
}
}