LeetCode 二叉树,两个子节点的最近的公共父节点
LeetCode 二叉树,两个子节点的最近的公共父节点
二叉树
Lowest Common Ancestor of a Binary Tree
二叉树的最近公共父亲节点
https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree
https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-tree
/**
* Definition for a binary tree node.
* function TreeNode(val) {
* this.val = val;
* this.left = this.right = null;
* }
*/
/**
* @param {TreeNode} root
* @param {TreeNode} p
* @param {TreeNode} q
* @return {TreeNode}
*/
var lowestCommonAncestor = function(root, p, q) {
let ancestor;
// DFS 深度优先搜索
const dfs = (root, p, q) => {
if (root === null) {
return false;
}
// 递归
const leftSon = dfs(root.left, p, q);
const rightSon = dfs(root.right, p, q);
if ((leftSon && rightSon) || ((root.val === p.val || root.val === q.val) && (leftSon || rightSon))) {
ancestor = root;
}
return leftSon || rightSon || (root.val === p.val || root.val === q.val);
}
dfs(root, p, q);
return ancestor;
};
solutions
- Recursive Approach
递归方法
- Iterative using parent pointers
使用父指针进行迭代
- Iterative without parent pointers
没有父指针的迭代
refs
https://leetcode-cn.com/problems/lowest-common-ancestor-of-a-binary-tree/solution/
https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/solution/
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