Find Missing Observations LeetCode solution in C++

1
class Solution {
2
 public:
3
  vector<int> missingRolls(vector<int> &rolls, int mean, int n) {
4
    int size = rolls.size(), sum = accumulate(rolls.begin(), rolls.end(), 0), missingSum = 0;
5
    missingSum = mean * (n + size) - sum;
6
    if (missingSum < n || missingSum > 6 * n) return {};
7
    int rem = missingSum % n;
8
    vector<int> ans(n, missingSum / n);
9
    for (int i = 0; i < rem; i++) ans[i] += 1;
10
    return ans;
11
  }
12
};