298. Binary Tree Longest Consecutive Sequence
2015-12-15 07:36
411 查看
题目:
Given a binary tree, find the length of the longest consecutive sequence path.
The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from parent to child (cannot be the reverse).
For example,
Longest consecutive sequence path is
Longest consecutive sequence path is
链接: http://leetcode.com/problems/binary-tree-longest-consecutive-sequence/
题解:
求二叉树中最长连续序列。 题目又比较长, 不过我们可以确定这个最长连续序列肯定是递增的,比如123,或者345。知道这点以后就可以用DFS遍历了。
Time Complexity - O(n), Space Complexity - O(n)。
Reference:
https://leetcode.com/discuss/68723/simple-recursive-dfs-without-global-variable https://leetcode.com/discuss/66486/c-solution-in-4-lines https://leetcode.com/discuss/66565/1ms-easy-understand-java-solution-just-traverse-the-tree-once https://leetcode.com/discuss/68094/dont-understand-what-is-consecutive-sequence https://leetcode.com/discuss/66646/two-simple-iterative-solutions-bfs-and-dfs https://leetcode.com/discuss/66548/recursive-solution-bottom-iteration-solution-using-stack https://leetcode.com/discuss/66584/easy-java-dfs-is-there-better-time-complexity-solution
Given a binary tree, find the length of the longest consecutive sequence path.
The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from parent to child (cannot be the reverse).
For example,
1 \ 3 / \ 2 4 \ 5
Longest consecutive sequence path is
3-4-5, so return
3.
2 \ 3 / 2 / 1
Longest consecutive sequence path is
2-3,not
3-2-1, so return
2.
链接: http://leetcode.com/problems/binary-tree-longest-consecutive-sequence/
题解:
求二叉树中最长连续序列。 题目又比较长, 不过我们可以确定这个最长连续序列肯定是递增的,比如123,或者345。知道这点以后就可以用DFS遍历了。
Time Complexity - O(n), Space Complexity - O(n)。
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { private int max = 0; public int longestConsecutive(TreeNode root) { if(root == null) { return max; } findLongestConsecutive(root, 0, root.val); return max; } private void findLongestConsecutive(TreeNode root, int curMax, int target) { if(root == null) { return; } if(root.val == target) { curMax++; } else { curMax = 1; } max = Math.max(max, curMax); findLongestConsecutive(root.left, curMax, root.val + 1); findLongestConsecutive(root.right, curMax, root.val + 1); } }
Reference:
https://leetcode.com/discuss/68723/simple-recursive-dfs-without-global-variable https://leetcode.com/discuss/66486/c-solution-in-4-lines https://leetcode.com/discuss/66565/1ms-easy-understand-java-solution-just-traverse-the-tree-once https://leetcode.com/discuss/68094/dont-understand-what-is-consecutive-sequence https://leetcode.com/discuss/66646/two-simple-iterative-solutions-bfs-and-dfs https://leetcode.com/discuss/66548/recursive-solution-bottom-iteration-solution-using-stack https://leetcode.com/discuss/66584/easy-java-dfs-is-there-better-time-complexity-solution
相关文章推荐
- iOS之UI--使用SWRevealViewController实现侧边菜单功能详解实例
- setProjectionMap@SQLiteQueryBuilder使用简记
- Android Service更新UI的方法之AIDL
- HDU 1242 Rescue
- UILabel的富文本设置
- UICollection 找不同--小游戏
- push to bluemix and get wrong
- Android开源之仿微信UI
- RequireJS笔记
- 认识String、StringBuilder、StringBuffer的区别
- [转载]基于MVC4+EasyUI的Web开发框架经验总结(8)--实现Office文档的预览
- UI基础-多线程
- php--关于include与require
- UIViewController的生命周期及iOS程序执行顺序
- iOS开发UI篇—核心动画(基础动画)
- toggle界面转化(UGUI)
- UINavigationController
- iOS开发UI篇—Quartz2D使用(绘图路径)
- call by value 和call by reference区别
- NGUI 背包系统的拖拽