102 lines
2.6 KiB
Java
102 lines
2.6 KiB
Java
package tree;
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import lombok.Data;
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import lombok.ToString;
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import java.util.List;
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import static tree.InorderTraversal.inorderTraversal1;
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/**
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* 删除二叉排序树的某个节点
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*/
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public class DeleteNode {
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public static void main(String[] args) {
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TreeNode root = new TreeNode(4);
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TreeNode TreeNode2 = new TreeNode(2);
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TreeNode TreeNode3 = new TreeNode(6);
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TreeNode TreeNode4 = new TreeNode(1);
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TreeNode TreeNode5 = new TreeNode(3);
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TreeNode TreeNode6 = new TreeNode(5);
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root.setLeft(TreeNode2);
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root.setRight(TreeNode3);
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TreeNode2.setLeft(TreeNode4);
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TreeNode2.setRight(TreeNode5);
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TreeNode3.setLeft(TreeNode6);
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deleteNode(root, 5);
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List<Integer> integers = inorderTraversal1(root);
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System.out.println(integers);
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}
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public static void deleteNode(TreeNode root, int value) {
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//删除的是有左右两个子树的节点
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TreeNode p = root;
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//记录当前节点的父节点
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TreeNode pp = null;
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//寻找到要删除的节点和他的父节点
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while (p != null && p.val != value) {
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pp = p;
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if (p.val < value) {
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p = p.right;
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} else if (p.val > value) {
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p = p.left;
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}
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}
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//判断是根据那个条件出来的
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if (p == null) {
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System.out.println("未找到要删除的节点的值...");
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return;
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} else if (p.val == value) {
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//p是要删除的节点,pp是他的父节点，如果pp=null,删除的就是root
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//判断删除的节点有几个子树
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if (p.left != null && p.right != null) {
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//左右子树都有,将找到右子树最小的节点，将他的值付给p，然后变成删除这个最小的数
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TreeNode min = p.right;
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//记录他的父节点
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TreeNode flag = p;
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while (min.left != null) {
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flag = min;
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min = min.left;
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}
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p.val = min.val;
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p = min;
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pp = flag;
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}
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//现在要删除的节点最多只有一个子树
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TreeNode child = null;
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if (p.left != null) {
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child = p.left;
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} else if (p.right != null) {
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child = p.right;
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}
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if (pp == null) {
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//要删除的是根节点
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root = child;
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} else if (pp.left == p) pp.left = child;
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else pp.right = child;
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}
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}
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}
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