You are given an integer array nums.
The alternating sum of nums is the value obtained by adding elements at even indices and subtracting elements at odd indices. That is, nums[0] - nums[1] + nums[2] - nums[3]...
Return an integer denoting the alternating sum of nums.
\n
Example 1:
\n\nInput: nums = [1,3,5,7]
\n\nOutput: -4
\n\nExplanation:
\n\nnums[0] = 1 and nums[2] = 5 because 0 and 2 are even numbers.nums[1] = 3 and nums[3] = 7 because 1 and 3 are odd numbers.nums[0] - nums[1] + nums[2] - nums[3] = 1 - 3 + 5 - 7 = -4.Example 2:
\n\nInput: nums = [100]
\n\nOutput: 100
\n\nExplanation:
\n\nnums[0] = 100 because 0 is an even number.nums[0] = 100.\n
Constraints:
\n\n1 <= nums.length <= 1001 <= nums[i] <= 100给你一个整数数组 nums。
交替和 定义为：将 nums 中偶数下标位置的元素 相加 ，减去 奇数下标位置的元素。即：nums[0] - nums[1] + nums[2] - nums[3]...
返回表示 nums 的交替和的整数。
\n\n
示例 1：
\n\n输入： nums = [1,3,5,7]
\n\n输出： -4
\n\n解释：
\n\nnums[0] = 1 和 nums[2] = 5，因为 0 和 2 是偶数。nums[1] = 3 和 nums[3] = 7，因为 1 和 3 是奇数。nums[0] - nums[1] + nums[2] - nums[3] = 1 - 3 + 5 - 7 = -4。示例 2：
\n\n输入： nums = [100]
\n\n输出： 100
\n\n解释：
\n\nnums[0] = 100，因为 0 是偶数。nums[0] = 100。\n\n
提示：
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