前往小程序,Get更优阅读体验!
立即前往
首页
学习
活动
专区
工具
TVP
发布
社区首页 >专栏 >Leetcode 236. Lowest Common Ancestor of a Binary Tree

Leetcode 236. Lowest Common Ancestor of a Binary Tree

作者头像
triplebee
发布2018-01-12 14:43:30
5540
发布2018-01-12 14:43:30
举报
文章被收录于专栏:计算机视觉与深度学习基础

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree.

According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w as descendants (where we allow a node to be a descendant of itself).”

代码语言:javascript
复制
        _______3______
       /              \
    ___5__          ___1__
   /      \        /      \
   6      _2       0       8
         /  \
         7   4

For example, the lowest common ancestor (LCA) of nodes 5 and 1 is 3. Another example is LCA of nodes 5 and 4 is 5, since a node can be a descendant of itself according to the LCA definition.

接235,找出二叉树上两个点的LCA,这次没有BST的性质可以使用了。

同样非常简单,只需要判断两个点是不是出现在二叉树的同一侧就行了。

代码语言:javascript
复制
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        if(!root) return NULL;
        if(p == root || q == root) return root;
        TreeNode* l = lowestCommonAncestor(root->left, p, q);
        TreeNode* r = lowestCommonAncestor(root->right, p, q);
        if(!l) return r;
        else if(!r) return l;
        else return root;
        
    }
};
本文参与 腾讯云自媒体同步曝光计划,分享自作者个人站点/博客。
原始发表:2017-04-06 ,如有侵权请联系 cloudcommunity@tencent.com 删除

本文分享自 作者个人站点/博客 前往查看

如有侵权,请联系 cloudcommunity@tencent.com 删除。

本文参与 腾讯云自媒体同步曝光计划  ,欢迎热爱写作的你一起参与!

评论
登录后参与评论
0 条评论
热度
最新
推荐阅读
领券
问题归档专栏文章快讯文章归档关键词归档开发者手册归档开发者手册 Section 归档