BST

package byown.practice;

public class TreeNode {
    char data;
    TreeNode left;
    TreeNode right;
    
    public TreeNode() {
        this.left = null;
        this.right = null;
    }
    
    public TreeNode(char data) {
        this.data = data;
        this.left = null;
        this.right = null;
    }
    
    public Object getData() {
        return data;
    }
}

package byown.practice;

public class BinarySearchTree {
    private TreeNode root = new TreeNode();
    
    public TreeNode insertKey(TreeNode root, char x) { 
        TreeNode p = root;
        TreeNode newNode = new TreeNode(x);
        
        if(p == null) {
            return newNode;
        } else if (p.data > newNode.data) {
            p.left = insertKey(p.left, x);
            return p;
        } else if (p.data < newNode.data) {
            p.right = insertKey(p.right, x);
            return p;
        } else {
            return p;
        }
    }
    
    public void insertBST(char x) {
        root = insertKey(root, x);
    }
    
    public TreeNode searchBST(char x) {
    	TreeNode p = root;
    	while (p != null) {
    		if(x < p.data) {
    			p = p.left;
    		}
    		else if (x > p.data) {
    			p = p.right;
    		}
    		else return p;
    	}
    	return p;
    }
    
    public void inorder(TreeNode root) {
    	if (root != null) {
    		inorder(root.left);
    		System.out.println(root.data + " ");
    		inorder(root.right);
    	}
    }
    
    public void printBST() {
    	inorder(root);
    	System.out.println();
    }
}

package byown.practice;

public class BstTest {
	
	public static void main(String[] args) {
		BinarySearchTree bst = new BinarySearchTree();
		
		bst.insertBST('G');
		bst.insertBST('I');
		bst.insertBST('H');
		bst.insertBST('D');
		bst.insertBST('B');
		bst.insertBST('M');
		bst.insertBST('N');
		bst.insertBST('A');
		bst.insertBST('J');
		bst.insertBST('E');
		bst.insertBST('Q');
		
		System.out.println("Binart Tree>>>");
		bst.printBST();
		
		System.out.println("Is There\"A\"?>>>");
		TreeNode p1 = bst.searchBST('A');
		if (p1 != null) {
			System.out.println(p1.data + "탐색 성공");
		}
		else {
			System.out.println("탐색 실패");
		}
		
		System.out.println("Is There\"Z\"?>>>");
		TreeNode p2 = bst.searchBST('Z');
		if (p2 != null) {
			System.out.println(p2.data + "탐색 성공");
		}
		else {
			System.out.println("탐색 실패");
		}
	}

}