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https://leetcode.com/problems/wiggle-subsequence/

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.

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12 > Examples:

> Input: [1,7,4,9,2,5]

> Output: 6

> The entire sequence is a wiggle sequence.

>

> Input: [1,17,5,10,13,15,10,5,16,8]

> Output: 7

> There 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?

#### java

0ms, September 11, 2016

https://discuss.leetcode.com/topic/51946/very-simple-java-solution-with-detail-explanation

1 | public class Solution { |

#### cpp

0ms, September 11, 2016

https://discuss.leetcode.com/topic/51893/two-solutions-one-is-dp-the-other-is-greedy-8-lines

1 | class Solution { |

13ms, September 11, 2016

https://discuss.leetcode.com/topic/51893/two-solutions-one-is-dp-the-other-is-greedy-8-lines

1 | class Solution { |