title: Maximum Area Rectangle Picking Four Sides Array 1
signature: function maximum_area_rectangle_picking_four_sides_array_1(arr, n)
source_py: def maximum_area_rectangle_picking_four_sides_array_1(arr, n):
      s = []
      first = 0
      second = 0
      for i in range(n):
          if (arr[i] not in s):
              s.append(arr[i])
              continue
          if (arr[i] > first):
              second = first
              first = arr[i]
          elif (arr[i] > second):
              second = arr[i]
      return (first * second)
source_cpp: int maximum_area_rectangle_picking_four_sides_array_1(vector<int> arr, int n) {
    unordered_set < int > s;
    int first = 0, second = 0;
    for ( int i = 0;
    i < n;
    i ++ ) {
      if ( s . find ( arr [ i ] ) == s . end ( ) ) {
        s . insert ( arr [ i ] );
        continue;
      }
      if ( arr [ i ] > first ) {
        second = first;
        first = arr [ i ];
      }
      else if ( arr [ i ] > second ) second = arr [ i ];
    }
    return ( first * second );
  }