376. Wiggle Subsequence
来源:互联网 发布:php报表 编辑:程序博客网 时间:2024/06/05 11:00
A sequence of numbers is called a wiggle sequence if the differences between successive numbers strictly alternate between positive and negative. The first difference (if one exists) may be either positive or negative. A sequence with fewer than two elements is trivially a wiggle sequence.
For example, [1,7,4,9,2,5] is a wiggle sequence because the differences (6,-3,5,-7,3) are alternately positive and negative. In contrast, [1,4,7,2,5] and [1,7,4,5,5] are not wiggle sequences, the first because its first two differences are positive and the second because its last difference is zero.
Given a sequence of integers, return the length of the longest subsequence that is a wiggle sequence. A subsequence is obtained by deleting some number of elements (eventually, also zero) from the original sequence, leaving the remaining elements in their original order.
Examples:
Input: [1,7,4,9,2,5]Output: 6The entire sequence is a wiggle sequence.Input: [1,17,5,10,13,15,10,5,16,8]Output: 7There are several subsequences that achieve this length. One is [1,17,10,13,10,16,8].Input: [1,2,3,4,5,6,7,8,9]Output: 2
Follow up:
Can you do it in O(n) time?
class Solution { public int wiggleMaxLength(int[] nums) { if(nums.length <= 1) return nums.length; int count = 1; Boolean prevInc = null; for(int i = 1; i < nums.length; i++) { if(nums[i] > nums[i - 1] && (prevInc == null || !prevInc)) { prevInc = true; count++; } else if(nums[i] < nums[i - 1] && (prevInc == null || prevInc)) { prevInc = false; count++; } } return count; }}
- leetcode 376. Wiggle Subsequence
- 376. Wiggle Subsequence
- leetcode 376. Wiggle Subsequence
- 376. Wiggle Subsequence
- [leetcode] 376. Wiggle Subsequence
- [LEETCODE] 376. Wiggle Subsequence
- [leetcode] 376. Wiggle Subsequence
- [leetcode] 376. Wiggle Subsequence
- LeetCode 376. Wiggle Subsequence
- leetcode 376. Wiggle Subsequence
- 376.[LeetCode]Wiggle Subsequence
- 376. Wiggle Subsequence
- 376. Wiggle Subsequence
- [Leetcode]376. Wiggle Subsequence
- 376. Wiggle Subsequence
- leetcode-376. Wiggle Subsequence
- Leetcode 376. Wiggle Subsequence
- 376. Wiggle Subsequence
- Android中Handler的源码解读
- Java面试题全集(中)
- echarts异步数据加载和更新
- 1336我已经不是三岁小孩了
- Python读取.xml文件(<?xml version="1.0" encoding="UTF-16"?>)中文乱码问题解决
- 376. Wiggle Subsequence
- POJ2239 Selecting Courses(二分图匹配,匈牙利算法)
- Windows下使用chkdsk修复移动硬盘/磁盘
- 【odds and ends】均方差和均方误差
- This is a prerequisite condition to test whether sufficient total swap space is available on system
- String.getBytes()与编码格式
- 【学习C++】继承与派生
- Java面试题全集(下)
- 【Android开发技巧】Fragment中获取Context对象的两种方法