You are given an integer array nums. You can choose exactly one index (0-indexed) and remove the element. Notice that the index of the elements may change after the removal.
For example, if nums = [6,1,7,4,1]:
An array is fair if the sum of the odd-indexed values equals the sum of the even-indexed values.
Return the number of indices that you could choose such that after the removal, nums is fair.
Examples
Example 1
Input: nums = [2,1,6,4]
Output: 1
Explanation:
Remove index 0: [1,6,4] -> Even sum: 1 + 4 = 5. Odd sum: 6. Not fair.
Remove index 1: [2,6,4] -> Even sum: 2 + 4 = 6. Odd sum: 6. Fair.
Remove index 2: [2,1,4] -> Even sum: 2 + 4 = 6. Odd sum: 1. Not fair.
Remove index 3: [2,1,6] -> Even sum: 2 + 6 = 8. Odd sum: 1. Not fair.
There is 1 index that you can remove to make nums fair.
Example 2
Input: nums = [1,1,1]
Output: 3
Explanation: You can remove any index and the remaining array is fair.
Example 3
Input: nums = [1,2,3]
Output: 0
Explanation: You cannot make a fair array after removing any index.
Constraints
1 <= nums.length <= 105
1 <= nums[i] <= 104
1664. Ways to Make a Fair Array
Medium
30 Points
Array
Prefix Sum
You are given an integer array nums. You can choose exactly one index (0-indexed) and remove the element. Notice that the index of the elements may change after the removal.
For example, if nums = [6,1,7,4,1]:
An array is fair if the sum of the odd-indexed values equals the sum of the even-indexed values.
Return the number of indices that you could choose such that after the removal, nums is fair.
Examples
Example 1
Input: nums = [2,1,6,4]
Output: 1
Explanation:
Remove index 0: [1,6,4] -> Even sum: 1 + 4 = 5. Odd sum: 6. Not fair.
Remove index 1: [2,6,4] -> Even sum: 2 + 4 = 6. Odd sum: 6. Fair.
Remove index 2: [2,1,4] -> Even sum: 2 + 4 = 6. Odd sum: 1. Not fair.
Remove index 3: [2,1,6] -> Even sum: 2 + 6 = 8. Odd sum: 1. Not fair.
There is 1 index that you can remove to make nums fair.
Example 2
Input: nums = [1,1,1]
Output: 3
Explanation: You can remove any index and the remaining array is fair.
Example 3
Input: nums = [1,2,3]
Output: 0
Explanation: You cannot make a fair array after removing any index.
Constraints
1 <= nums.length <= 105
1 <= nums[i] <= 104
Ways to Make a Fair Array - Practice Coding | SlaveCode