Multiple blockers and trample
You have to assign lethal combat damage to all blocking creatures before you can assign any to the player.  From the rules (emphasis mine):


  702.19b The controller of an attacking creature with trample first assigns damage to the creature(s) blocking it. Once all those blocking
  creatures are assigned lethal damage, any remaining damage is assigned
  as its controller chooses among those blocking creatures and the
  player or planeswalker the creature is attacking. When checking for
  assigned lethal damage, take into account damage already marked on the
  creature and damage from other creatures that’s being assigned during
  the same combat damage step, but not any abilities or effects that
  might change the amount of damage that’s actually dealt. The attacking
  creature’s controller need not assign lethal damage to all those
  blocking creatures but in that case can’t assign any damage to the
  player or planeswalker it’s attacking.


Short answer: no, you can't assign 0 to the 2/2 and the 3/3 and still hit the defending player.  You have to assign enough damage to all the blockers to otherwise kill them before you can assign any leftover damage to the player.