Index with Equal Left and Right Sums
Given a list of integer nums, return the earliest index i such that the sum of the numbers left of i is equal to the sum of numbers right of i. If there’s no solution, return -1.
Sum of an empty list is defined to be 0.
Constraints
1 ≤ n ≤ 100,000wherenis the length ofnums
https://binarysearch.com/problems/Index-with-Equal-Left-and-Right-Sums
ExamplesPermalink
Example 1Permalink
Input
- nums =
[2, 3, 4, 0, 5, 2, 2]
Output
- answer =
3
Explanation
Sum of the numbers left of index 3 is 9 and sum of the numbers right of index 3 also 9.
Example 2Permalink
Input
- nums =
[1, -2, 2]
Output
- answer =
0
Explanation
Sum of the numbers left of index 0 is 0 and sum of the numbers right of index 0 also 0.
SolutionPermalink
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| int solve(vector<int> &nums) | |
| { | |
| int rightSum = accumulate(nums.begin(), nums.end(), 0); | |
| int leftSum = 0; | |
| for (int i = 0; i < nums.size(); i++) | |
| { | |
| rightSum -= nums[i]; | |
| leftSum += nums[i]; | |
| if (rightSum == leftSum - nums[i]) | |
| return i; | |
| } | |
| return -1; | |
| } |
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