2028 - Find Missing Observations

 JAVA

• class Solution {
      public int[] missingRolls(int[] rolls, int mean, int n) {
          int m = rolls.length;
          int s = (n + m) * mean;
          for (int v : rolls) {
              s -= v;
          }
          if (s > n * 6 || s < n) {
              return new int[0];
          }
          int[] ans = new int[n];
          Arrays.fill(ans, s / n);
          for (int i = 0; i < s % n; ++i) {
              ++ans[i];
          }
          return ans;
      }
  }

C++

• class Solution {
  public:
      vector<int> missingRolls(vector<int>& rolls, int mean, int n) {
          int m = rolls.size();
          int s = (n + m) * mean;
          for (int& v : rolls) s -= v;
          if (s > n * 6 || s < n) return {};
          vector<int> ans(n, s / n);
          for (int i = 0; i < s % n; ++i) ++ans[i];
          return ans;
      }
  };