第19题 在二叉查找树中找到两个结点的最低公共祖先 Lowest Common Ancestor
2012-03-18 05:44
363 查看
本文来自《 programming interviews exposed》一书
题目:
Given the value of two nodes in a binary search tree, find the lowest common ancestor. You may assume that both values already exist in the tree.
The function prototype is as follows:
20
/ \
8 22
/ \
4 12
/ \
10 14
比如在上面这个二叉搜索树中,要找4和14的lowest common ancestor, 就应该是8.
算法描述:
因为根节点是所有节点的祖先,又因为二叉树自身的性质,我们会得到,当两个目标节点都比当前节点小的时候,我们走左节点,当两个目标节点都比当前节点大的时候,我们走右节点。第一个碰到的节点的值在两个目标节点之间的节点就是 lowest common ancestor
算法的时间复杂度是O(logn)
题目:
Given the value of two nodes in a binary search tree, find the lowest common ancestor. You may assume that both values already exist in the tree.
The function prototype is as follows:
int findLowestCommonAncestor(node* root, int value 1, int value2);
20
/ \
8 22
/ \
4 12
/ \
10 14
比如在上面这个二叉搜索树中,要找4和14的lowest common ancestor, 就应该是8.
算法描述:
因为根节点是所有节点的祖先,又因为二叉树自身的性质,我们会得到,当两个目标节点都比当前节点小的时候,我们走左节点,当两个目标节点都比当前节点大的时候,我们走右节点。第一个碰到的节点的值在两个目标节点之间的节点就是 lowest common ancestor
int findLowestCommonAncestor(node* root, int value1, int value2) { node* curNode = root; while(1) { // go to the left child if(curNode->value>value1 && curNode->value>value2) curNode = curNode->left; // go to the right child else if (curNode->value < value1 && curNode->value < value2) curNode = curNode->right; else return curNode->value; } }
算法的时间复杂度是O(logn)
相关文章推荐
- Lowest Common Ancestor of a Binary Search Tree(树中两个结点的最低公共祖先)
- 面试题50 树中两个节点的最低公共祖先LCA(Lowest Common Ancestor )
- 235. Lowest Common Ancestor of a Binary Search Tree | 二叉查找树两个节点的最低共同祖先
- 寻找二叉树中的最低公共祖先结点----LCA(Lowest Common Ancestor )问题(递归)
- [Java]寻找最低公共祖先(排序二叉树)Lowest Common Ancestor of a Binary Search Tree
- [Java]寻找最低公共祖先(普通树的情形)Lowest Common Ancestor of a Binary Tree
- 235. Lowest Common Ancestor of a Binary Search Tree (求二叉树中两个节点的最近公共祖先)
- PAT 1143—— Lowest Common Ancestor(二叉排序树 + 最低公共祖先)
- Lowest Common Ancestor of a Binary Search Tree 递归寻找二叉查找树公共祖先
- 最低公共祖先 lowest common ancestor
- 235. Lowest Common Ancestor of a Binary Search Tree(LCA最低公共祖先)
- LeetCode 235. Lowest Common Ancestor of a Binary Search Tree(二叉搜索树的最低公共祖先)
- LeetCode 236. Lowest Common Ancestor of a Binary Tree(二叉树的最低公共祖先)
- 236. Lowest Common Ancestor of a Binary Tree(最低公共祖先,难理解)
- 235. Lowest Common Ancestor of a Binary Search Tree 二叉搜索树的最低公共祖先(难)
- 最低公共祖先Lowest Common Ancestor of a Binary Tree
- 树中两个结点的最低公共祖先(剑指offer!!!)
- 案例二 树中两个结点的最低公共祖先
- Tree_Graph LCA(Lowest Common Ancestor) 最低公共节点 (BST或者一般树) @CareerCup
- Range Minimum Query and Lowest Common Ancestor 区间最值查询和最近公共祖先问题