Program: 112796
Project: 112796
Buggy source:
/** 
 * Use the hero ability on a given target Warlock: place random totem on the board
 * @param targetPlayerIndex The player index of the target character
 * @param targetMinion The target minion
 * @param boardState
 * @param deckPlayer0
 * @param deckPlayer1
 * @return
 */
@Override public HearthTreeNode useHeroAbility_core(int targetPlayerIndex,Minion targetMinion,HearthTreeNode boardState,Deck deckPlayer0,Deck deckPlayer1,boolean singleRealizationOnly) throws HSException {
  if (targetPlayerIndex != 0 || !(targetMinion instanceof Hero))   return null;
  int numMinions=boardState.data_.getNumMinions(targetPlayerIndex);
  if (numMinions >= 7) {
    return null;
  }
  if (singleRealizationOnly) {
    HearthTreeNode toRet=boardState;
    Minion minionToSummon=null;
    Minion[] allTotems={new SearingTotem(),new StoneclawTotem(),new HealingTotem(),new WrathOfAirTotem()};
    for (int i=allTotems.length - 1; i > 0; --i) {
      int j=(int)(Math.random() * (i + 1));
      Minion ci=allTotems[i];
      allTotems[i]=allTotems[j];
      allTotems[j]=ci;
    }
    for (int index=0; index < 4; ++index) {
      boolean totemAlreadySummoned=false;
      for (      Minion minion : toRet.data_.getMinions(targetPlayerIndex)) {
        if (minion.getClass().equals(allTotems[index].getClass())) {
          totemAlreadySummoned=true;
        }
      }
      if (!totemAlreadySummoned) {
        minionToSummon=allTotems[index];
        break;
      }
    }
    if (minionToSummon == null)     return null;
    this.hasBeenUsed_=true;
    toRet.data_.setMana_p0(toRet.data_.getMana_p0() - HERO_ABILITY_COST);
    Minion summonTarget=toRet.data_.getCharacter(targetPlayerIndex,numMinions);
    toRet=minionToSummon.summonMinion(targetPlayerIndex,summonTarget,toRet,deckPlayer0,deckPlayer1,false);
    return toRet;
  }
  HearthTreeNode toRet=new RandomEffectNode(boardState,new HearthAction(HearthAction.Verb.HERO_ABILITY,0,0,targetPlayerIndex,0));
  if (toRet != null) {
    this.hasBeenUsed_=true;
    Minion[] minions={new SearingTotem(),new StoneclawTotem(),new HealingTotem(),new WrathOfAirTotem()};
    boolean allTotemsNotSummonable=true;
    for (    Minion minionToSummon : minions) {
      boolean totemAlreadySummoned=false;
      for (      Minion minion : toRet.data_.getMinions(targetPlayerIndex)) {
        if (minion.getClass().equals(minionToSummon.getClass())) {
          totemAlreadySummoned=true;
        }
 else {
          allTotemsNotSummonable=false;
        }
      }
      if (allTotemsNotSummonable)       return null;
      if (!totemAlreadySummoned) {
        HearthTreeNode newState=toRet.addChild(new HearthTreeNode((BoardState)toRet.data_.deepCopy()));
        Minion summonTarget=newState.data_.getCharacter(targetPlayerIndex,numMinions);
        newState.data_.setMana_p0(newState.data_.getMana_p0() - HERO_ABILITY_COST);
        newState=minionToSummon.summonMinion(targetPlayerIndex,summonTarget,newState,deckPlayer0,deckPlayer1,false);
      }
    }
  }
  return toRet;
}

Fixed version (ground truth):
/** 
 * Use the hero ability on a given target Warlock: place random totem on the board
 * @param targetPlayerIndex The player index of the target character
 * @param targetMinion The target minion
 * @param boardState
 * @param deckPlayer0
 * @param deckPlayer1
 * @return
 */
@Override public HearthTreeNode useHeroAbility_core(int targetPlayerIndex,Minion targetMinion,HearthTreeNode boardState,Deck deckPlayer0,Deck deckPlayer1,boolean singleRealizationOnly) throws HSException {
  if (targetPlayerIndex != 0 || !(targetMinion instanceof Hero))   return null;
  int numMinions=boardState.data_.getNumMinions(targetPlayerIndex);
  if (numMinions >= 7) {
    return null;
  }
  if (singleRealizationOnly) {
    HearthTreeNode toRet=boardState;
    Minion minionToSummon=null;
    Minion[] allTotems={new SearingTotem(),new StoneclawTotem(),new HealingTotem(),new WrathOfAirTotem()};
    for (int i=allTotems.length - 1; i > 0; --i) {
      int j=(int)(Math.random() * (i + 1));
      Minion ci=allTotems[i];
      allTotems[i]=allTotems[j];
      allTotems[j]=ci;
    }
    for (int index=0; index < 4; ++index) {
      boolean totemAlreadySummoned=false;
      for (      Minion minion : toRet.data_.getMinions(targetPlayerIndex)) {
        if (minion.getClass().equals(allTotems[index].getClass())) {
          totemAlreadySummoned=true;
        }
      }
      if (!totemAlreadySummoned) {
        minionToSummon=allTotems[index];
        break;
      }
    }
    if (minionToSummon == null)     return null;
    this.hasBeenUsed_=true;
    toRet.data_.setMana_p0(toRet.data_.getMana_p0() - HERO_ABILITY_COST);
    Minion summonTarget=toRet.data_.getCharacter(targetPlayerIndex,numMinions);
    toRet=minionToSummon.summonMinion(targetPlayerIndex,summonTarget,toRet,deckPlayer0,deckPlayer1,false);
    return toRet;
  }
  HearthTreeNode toRet=new RandomEffectNode(boardState,new HearthAction(HearthAction.Verb.HERO_ABILITY,0,0,targetPlayerIndex,0));
  if (toRet != null) {
    Minion[] totems={new SearingTotem(),new StoneclawTotem(),new HealingTotem(),new WrathOfAirTotem()};
    boolean allTotemsNotSummonable=true;
    for (    Minion totemToSummon : totems) {
      boolean totemAlreadySummoned=false;
      for (      Minion minion : toRet.data_.getMinions(targetPlayerIndex)) {
        if (minion.getClass().equals(totemToSummon.getClass())) {
          totemAlreadySummoned=true;
          break;
        }
      }
      if (!totemAlreadySummoned) {
        allTotemsNotSummonable=false;
        HearthTreeNode newState=toRet.addChild(new HearthTreeNode((BoardState)toRet.data_.deepCopy()));
        Minion summonTarget=newState.data_.getCharacter(targetPlayerIndex,numMinions);
        newState.data_.setMana_p0(newState.data_.getMana_p0() - HERO_ABILITY_COST);
        newState.data_.getHero_p0().hasBeenUsed(true);
        newState=totemToSummon.summonMinion(targetPlayerIndex,summonTarget,newState,deckPlayer0,deckPlayer1,false);
      }
    }
    if (allTotemsNotSummonable)     return null;
  }
  return toRet;
}