二叉树的删除

package sy3.sy;

import javax.print.attribute.standard.NumberUp;
import java.util.PriorityQueue;
import java.util.function.ObjDoubleConsumer;

//节点类
public class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;

    public TreeNode(int val) {
        this.val = val;
    }

    
    public void add(TreeNode node) {
        if (node == null) {
            return;
        }
        if (node.val < this.val) {
            if (this.left == null) {
                this.left = node;
            } else {
                this.left.add(node);
            }
        } else {
            if (this.right == null) {
                this.right = node;
            } else {
                this.right.add(node);
            }
        }
    }

    
    public TreeNode search(int val) {
        if (this.val == val) {
            return this;
        }
        if (this.val < val) {
            if (this.right == null) {
                return null;
            }
            return this.right.search(val);
        } else {
            if (this.left == null) {
                return null;
            }
            return this.left.search(val);
        }
    }

    
    public TreeNode searchParent(int val) {
        if (this.left != null && this.left.val == val || this.right != null && this.right.val == val) {
            return this;
        } else {
            if (val < this.val && this.left != null) {
                return this.left.searchParent(val);
            } else {
                if (val > this.val && this.right != null) {
                    return this.right.searchParent(val);
                }
            }
        }
        return null;
    }

}

//创建二叉树
class Creat {
    private TreeNode root;

    public TreeNode getRoot() {
        return root;
    }

    
    public void add(TreeNode node) {
        if (root == null) {
            root = node;
        } else {
            root.add(node);
        }
    }

    
    public int delRightTreeMin(TreeNode node) {
        TreeNode target = node;
        while (target.left != null) {
            target = target.left;
        }
        delNode(target.val);
        return target.val;
    }

    public void delNode(int val) {
        if (root == null) {
            return;
        }
        TreeNode targetNode = search(val);
        if (targetNode == null) {
            return;
        }
        if (root.left == null && root.right == null) {
            root = null;
            return;
        }
        TreeNode parent = searchParent(val);
        //删除叶子节点
        if (targetNode.left == null && targetNode.right == null) {
            if (parent.left != null && parent.left.val == val) {
                parent.left = null;
            } else if (parent.right != null && parent.right.val == val) {
                parent.right = null;
            }
            //删除有两个子节点的节点
        } else if (targetNode.right != null && targetNode.left != null) {
            int minVal = delRightTreeMin(targetNode.right);
            targetNode.val = minVal;
        } else {
            //删除的节点有一个左节点
            if (targetNode.left != null) {
                if (parent != null) {
                    if (parent.left.val == val) {
                        parent.left = targetNode.left;
                    } else {
                        parent.right = targetNode.left;
                    }
                } else {
                    root = targetNode.left;
                }
            } else {
                //要删除的有一个右子节点
                if (parent != null) {
                    if (parent.left.val == val) {
                        parent.left = targetNode.right;//正常删除
                    } else {
                        parent.right = targetNode.right; //parent的右边的右节点
                    }
                } else {
                    root = targetNode.right;
                }
            }
        }

    }

    public TreeNode search(int val) {
        if (root == null) {
            return null;
        } else {
            return root.search(val);
        }
    }

    public TreeNode searchParent(int val) {
        if (root == null) {
            return null;
        }
        return root.searchParent(val);
    }

    
    public void pre(TreeNode node) {
        if (node == null) {
            return;
        }
        System.out.print(node.val + " ");
        pre(node.left);
        pre(node.right);
    }

    
    public void order(TreeNode node) {
        if (node == null) {
            return;
        }
        order(node.left);
        System.out.print(node.val + " ");
        order(node.right);
    }
}

class Test {
    public static void main(String[] args) {
        int[] arr = {7, 3, 10, 12, 5, 1, 9, 2};
        Creat c = new Creat();
        for (int i = 0; i < arr.length; i++) {
            c.add(new TreeNode(arr[i]));
        }
        TreeNode root = c.getRoot();
//        c.order(root);
        TreeNode search = c.search(2);
//        System.out.println(search.val);
//        TreeNode treeNode = c.searchParent(5);
//        System.out.println(treeNode.val);
//        int i = c.delRightTreeMin(root);
//        System.out.println(i);
        c.delNode(7);
        c.order(root);
    }
}