代码随想录算法训练营第二十天

LeetCode.235  二叉搜索树的最近公共祖先

题目链接  二叉搜索树的最近公共祖先

题解

class Solution {public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {if(root.val > p.val && root.val > q.val) return lowestCommonAncestor(root.left,p,q);if(root.val < p.val && root.val < q.val) return lowestCommonAncestor(root.right,p,q);return root;}
}

LeetCode.701 二叉搜索树中的插入操作

题目链接 二叉搜索树中的插入操作

题解

class Solution {public TreeNode insertIntoBST(TreeNode root, int val) {if(root == null) {return new TreeNode(val);}if(root.val > val)  root.left = insertIntoBST(root.left,val);if(root.val < val) root.right = insertIntoBST(root.right,val);return root;}
}

LeetCode.450 删除二叉搜索树中的节点

题目链接 删除二叉搜索树中的节点

题解

class Solution {public TreeNode deleteNode(TreeNode root, int key) {if(root == null) return null;if(root.val == key) {deleteNode(root.right,key);deleteNode(root.left,key);}root.left = deleteNode(root.left,key);root.right = deleteNode(root.right,key);return root;}
}