diff --git a/problems/0226.翻转二叉树.md b/problems/0226.翻转二叉树.md index 8e35fc9d..83d20df8 100644 --- a/problems/0226.翻转二叉树.md +++ b/problems/0226.翻转二叉树.md @@ -470,25 +470,14 @@ func invertTree(root *TreeNode) *TreeNode { 使用递归版本的前序遍历 ```javascript var invertTree = function(root) { - //1. 首先使用递归版本的前序遍历实现二叉树翻转 - //交换节点函数 - const inverNode=function(left,right){ - let temp=left; - left=right; - right=temp; - //需要重新给root赋值一下 - root.left=left; - root.right=right; + // 终止条件 + if (!root) { + return null; } - //确定递归函数的参数和返回值inverTree=function(root) - //确定终止条件 - if(root===null){ - return root; - } - //确定节点处理逻辑 交换 - inverNode(root.left,root.right); - invertTree(root.left); - invertTree(root.right); + // 交换左右节点 + const rightNode = root.right; + root.right = invertTree(root.left); + root.left = invertTree(rightNode); return root; }; ``` diff --git a/problems/0450.删除二叉搜索树中的节点.md b/problems/0450.删除二叉搜索树中的节点.md index 3fa2a1c5..3bc8369c 100644 --- a/problems/0450.删除二叉搜索树中的节点.md +++ b/problems/0450.删除二叉搜索树中的节点.md @@ -456,31 +456,42 @@ func deleteNode(root *TreeNode, key int) *TreeNode { * @param {number} key * @return {TreeNode} */ -var deleteNode = function (root, key) { - if (root === null) - return root; - if (root.val === key) { - if (!root.left) - return root.right; - else if (!root.right) - return root.left; - else { - let cur = root.right; - while (cur.left) { - cur = cur.left; - } - cur.left = root.left; - root = root.right; - delete root; - return root; - } - } - if (root.val > key) - root.left = deleteNode(root.left, key); - if (root.val < key) +var deleteNode = function(root, key) { + if (!root) return null; + if (key > root.val) { root.right = deleteNode(root.right, key); - return root; + return root; + } else if (key < root.val) { + root.left = deleteNode(root.left, key); + return root; + } else { + // 场景1: 该节点是叶节点 + if (!root.left && !root.right) { + return null + } + // 场景2: 有一个孩子节点不存在 + if (root.left && !root.right) { + return root.left; + } else if (root.right && !root.left) { + return root.right; + } + // 场景3: 左右节点都存在 + const rightNode = root.right; + // 获取最小值节点 + const minNode = getMinNode(rightNode); + // 将待删除节点的值替换为最小值节点值 + root.val = minNode.val; + // 删除最小值节点 + root.right = deleteNode(root.right, minNode.val); + return root; + } }; +function getMinNode(root) { + while (root.left) { + root = root.left; + } + return root; +} ``` 迭代