Class Solution
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- g1901_2000.s1911_maximum_alternating_subsequence_sum.Solution
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public class Solution extends Object
1911 - Maximum Alternating Subsequence Sum.Medium
The alternating sum of a 0-indexed array is defined as the sum of the elements at even indices minus the sum of the elements at odd indices.
- For example, the alternating sum of
[4,2,5,3]is(4 + 5) - (2 + 3) = 4.
Given an array
nums, return the maximum alternating sum of any subsequence ofnums(after reindexing the elements of the subsequence).A subsequence of an array is a new array generated from the original array by deleting some elements (possibly none) without changing the remaining elements’ relative order. For example,
[2,7,4]is a subsequence of[4,2,3,7,2,1,4](the underlined elements), while[2,4,2]is not.Example 1:
Input: nums = [4,2,5,3]
Output: 7
Explanation: It is optimal to choose the subsequence [4,2,5] with alternating sum (4 + 5) - 2 = 7.
Example 2:
Input: nums = [5,6,7,8]
Output: 8
Explanation: It is optimal to choose the subsequence [8] with alternating sum 8.
Example 3:
Input: nums = [6,2,1,2,4,5]
Output: 10
Explanation: It is optimal to choose the subsequence [6,1,5] with alternating sum (6 + 5) - 1 = 10.
Constraints:
1 <= nums.length <= 1051 <= nums[i] <= 105
- For example, the alternating sum of
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Constructor Summary
Constructors Constructor Description Solution()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description longmaxAlternatingSum(int[] nums)
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