Notes

package Tree;

public class Node {

public int data;
public Node leftChild;
public Node rightChild;

public void displayNode() {

System.out.println("{");

System.out.println(data);

System.out.println("}");
}

}
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package Tree;

public class Tree {

Node root;

public Node minimum() {

Node current=root;

Node last=null;

while(current!=null) {

last=current;

current=current.leftChild;
}

return last;
}

public Node minRec(Node root) {

if(root.leftChild==null) {

return root;
}

return minRec(root.leftChild);
}

public boolean delete(int key) {

Node current=root;

Node parent=root;

boolean isleftChild=true;

while(current.data!=key) {

parent=current;

if(key<current.data) {

isleftChild=true;

current=current.leftChild;
}

else {

isleftChild=false;

current=current.rightChild;

}

if(current==null) {

return false;
}
}

if(current.leftChild==null && current.rightChild==null) {

if(current==root) {

root=null;
} else if (isleftChild){

parent.leftChild=null;
} else {

parent.rightChild=null;
}
}

else if(current.rightChild==null) {

if(current==root) {

root=current.leftChild;
} else if(isleftChild) {

parent.leftChild=current.leftChild;
} else {

parent.rightChild=current.leftChild;
}
}

else if(current.leftChild==null) {

if(current==root) {

root=current.rightChild;
} else if(isleftChild) {

parent.leftChild=current.rightChild;
} else {

parent.rightChild=current.rightChild;
}
}

else {

Node succesor=getSuccesor(current);

if(current==root) {

root=succesor;
} else if(isleftChild){

parent.leftChild=succesor;
} else {

parent.rightChild=succesor;
}

succesor.leftChild=current.leftChild;
}

return true;
}

private Node getSuccesor(Node delNode) {

Node succesorParent=delNode;

Node succesor=delNode;

Node current=delNode.rightChild;

while(current!=null) {

succesorParent=succesor;

succesor=current;

current=current.leftChild;
}

if(succesor!=delNode.rightChild) {

succesorParent.leftChild=succesor.rightChild;

succesor.rightChild=delNode.rightChild;
}

return succesor;
}

public void displayNode() {

System.out.println(root);
}

}

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package Tree;

public class TreeApp {

public static void main(String[] args) {

Tree theTree=new Tree();

theTree.insert(50);
theTree.insert(37);
theTree.insert(21);
theTree.insert(45);
theTree.insert(65);
theTree.insert(64);
theTree.insert(70);
theTree.insert(80);
theTree.insert(90);
theTree.insert(95);

theTree.minimum().displayNode();;
}

}