title: Subarrays Distinct Elements
signature: function subarraysDistinctElements(arr, n) {
source_py: def subarrays_distinct_elements(arr, n):
      s = []
      j = 0
      ans = 0
      for i in range(n):
          while ((j < n) and (arr[j] not in s)):
              s.append(arr[j])
              j += 1
          ans += (((j - i) * ((j - i) + 1)) // 2)
          s.remove(arr[i])
      return ans
source_cpp: int subarrays_distinct_elements(vector<int> arr, int n) {
    unordered_set < int > s;
    int j = 0, ans = 0;
    for ( int i = 0;
    i < n;
    i ++ ) {
      while ( j < n && s . find ( arr [ j ] ) == s . end ( ) ) {
        s . insert ( arr [ j ] );
        j ++;
      }
      ans += ( ( j - i ) * ( j - i + 1 ) ) / 2;
      s . erase ( arr [ i ] );
    }
    return ans;
  }