public SearchState(ArmyBlueprint army, NationBlueprint defender, int depth, SearchState parent, InvasionWave fromParent)
{
if (depth == 0)
{
sStateNumber = 0;
}
mStateNumber = sStateNumber++;
Depth = depth;
Prob = new Prob(army, defender);
ParentProblem = parent;
TransitionFromParent = fromParent != null ? new InvasionWave(fromParent.Wave) : null;
}
/*
* Driver for recursive division of invading army into all possible sub army invasions
* Does future checks to see if there will ever be a valid solution coming from this leaf.
* example: Checks if the army will ever be able to capture the strongest city
*/
public List <SearchState> Fdiv(SearchState state, bool keepArmyTogether)
{
//Debug.Assert(!state.IsSolved, "Attempting to apply Div on a solved problem");
// Get all attackable forts
List <Fortification> fortifications = new List <Fortification>(state.Prob.NationBlueprint.GetBorderCities());
ArmyBlueprint invadingArmy = state.Prob.InvadingArmy;
fortifications.Add(new Fortification()); // add a place holder fort for units to be held in reserve
List <SearchState> problemDivisions = new List <SearchState>();
// TODO: pick most difficult city to capture. Temp patch just check the first
Fortification hardestCity = fortifications[0];
// Since damage doesn't increase over time, if the army can't take the city now it will never be able to
if (!mIsOptimized && invadingArmy.Damage < hardestCity.Defense)
{
return(problemDivisions);
}
// If the army is strong enough to take the city but doesn't have enough health,
// and it either can't heal, or it's max health even after healing wont be enough to take the city,
// abandon this search
else if (!mIsOptimized && invadingArmy.Health <= hardestCity.Offense &&
!(invadingArmy.CanHeal && invadingArmy.MaxHealth > hardestCity.Offense))
{
return(problemDivisions);
}
// come up with all possible transitions through recursing through all army combinations
else
{
List <InvasionWave> armyDistributions = new List <InvasionWave>();
RecurseFdiv(
new ArmyBlueprint(invadingArmy.Soldiers, invadingArmy.Healers, invadingArmy.Archers),
0, fortifications, new InvasionWave(), armyDistributions, keepArmyTogether);
foreach (InvasionWave transition in armyDistributions)
{
SearchState nextState = Ftrans(state, transition);
// if the transition proved to be wasteful, discard
if (nextState != null)
{
problemDivisions.Add(nextState);
}
}
}
return(problemDivisions);
}
// Helper function to convert the invasion stack into a solution
public static InvasionSolution ToSolution(SearchState state, ArmyBlueprint initialArmy, NationBlueprint initialNation)
{
SearchState currentState = state;
List <InvasionWave> invasionOrder = new List <InvasionWave>();
while (currentState.TransitionFromParent != null)
{
invasionOrder.Add(currentState.TransitionFromParent);
currentState = currentState.ParentProblem;
}
invasionOrder.Reverse();
return(new InvasionSolution(initialArmy, initialNation,
state.Prob.InvadingArmy, state.Prob.NationBlueprint,
invasionOrder, state.IsSolved));
}
/*
* Driver for search logic.
* i) Check if the chosen state is solved, and if so update solution records accordiningly
* ii) If not solved, check for preliminary qualities that would disqualify this sub problem from being searched
* iii) If not disqualified, run a recursive division on the invading army into all possible invasion groupings
* Each combination found will be added as a new leaf on the tree
*/
public void Search(SearchState chosenState, bool keepArmyTogether)
{
if (chosenState.IsSolved)
{
mNumLeafsCreated++;
#region SolutionFound
// Check if the solution is relevant depending on which optimizations are being used and solution quality
bool updateSolution = false;
bool recordSolution = false;
int numStepsInInvasion = chosenState.Depth;
if (mBestSolution == null) // havent found a solution yet
{
recordSolution = updateSolution = true;
if (mIsOptimized)
{
// only accept solutions that occur in as many turns as the new solution
mMaxDepthOfTree = numStepsInInvasion;
}
}
else if (numStepsInInvasion < mBestSolutionDepth) // found a quicker invasion strategy
{
recordSolution = updateSolution = true;
mBestSolution = null;
// reset solution tracking
if (mIsOptimized)
{
mNumSolutionsFound = 0;
mMaxDepthOfTree = numStepsInInvasion;
}
}
else if (mBestSolutionDepth == numStepsInInvasion) // occurs in the same number of turns as previous solutions
{
recordSolution = true;
if (chosenState.Prob.InvadingArmy.CalculateArmyValue() > mBestSolutionArmyValue)
{
updateSolution = true;
}
}
else // worse quality of solution
{
recordSolution = !mIsOptimized;
}
if (recordSolution)
{
mNumSolutionsFound++;
}
// Create and store new solution
if (updateSolution)
{
mBestSolution = ToSolution(chosenState, mInitialArmy, mInitialNation);
mBestSolutionDepth = numStepsInInvasion;
mBestSolutionArmyValue = chosenState.Prob.InvadingArmy.CalculateArmyValue();
}
#endregion
}
else // sub problem is not solved. Check if sub problem can be divided
{
if (mBestSolution == null) // record partial solutions until an actual solution is found
{
if (mBestPartialSolution == null)
{
mBestPartialSolution = chosenState;
mBestPartialSolutionValue = chosenState.Prob.ProblemValue;
}
else
{
// only update partial solution if it was able to take more cities than the previous, regardless of better army value
if (chosenState.Prob.NationBlueprint.NumCitiesRemaining < mBestPartialSolution.Prob.NationBlueprint.NumCitiesRemaining)
{
float probValue = chosenState.Prob.ProblemValue;
if (probValue < mBestPartialSolutionValue)
{
mBestPartialSolution = chosenState;
mBestPartialSolutionValue = probValue;
}
}
}
}
// check for disqualifying features of invasion state
bool validState = true;
if (chosenState.ParentProblem != null)
{
if (chosenState.ParentProblem.StateValue == chosenState.StateValue) // army did not heal nor was a city taken
{
// do nothing, this state didn't progress the invasion
validState = false;
}
}
// took more turns to complete than our max turn limit
if (mMaxDepthOfTree != -1 && mIsOptimized && chosenState.Depth >= mMaxDepthOfTree)
{
validState = false;
}
// valid subproblem. Add all new leafs possible from this state
if (validState)
{
List <SearchState> subProblems = Fdiv(chosenState, keepArmyTogether);
mNumLeafsCreated += subProblems.Count;
foreach (SearchState subProblem in subProblems)
{
mOpenLeafs.AddLast(subProblem);
}
}
else
{
mNumLeafsCreated++;
}
}
}
public SearchResults SearchForSolutions(ArmyBlueprint attackers, NationBlueprint defenders, bool optimize)
{
mInitialArmy = attackers;
mInitialNation = defenders;
mIsOptimized = true; /* = optimize; Replace after data collection*/
// Initialize start variables and start invasion search
SearchState initialState = new SearchState(attackers, defenders, 0, null, null);
mOpenLeafs.Clear();
// orrient the nations layout relative to the army. TODO: allow for dynamic invasion direction
initialState.Prob.NationBlueprint.BeginInvasion(Vector2.right);
// Do the default search keeping the units together
mOpenLeafs.AddLast(initialState);
mPruneSolutions = true; // only care about the best solution with army grouped up. Only record
mMaxDepthOfTree = mBestSolutionDepth = -1; // max depth = -1 until a solution is found creating a limit to depth
// Search for solutions with linear invasion strategy
while (mOpenLeafs.Count > 0)
{
SearchState pop = mOpenLeafs.Last.Value;
mOpenLeafs.RemoveLast();
Search(pop, true);
}
// record default invasion stats
InvasionSolution linearSolution = null;
if (mBestSolution == null) // no solution was found
{
// record the best result possible
linearSolution = ToSolution(mBestPartialSolution, mInitialArmy, mInitialNation);
}
else
{
linearSolution = mBestSolution;
}
int bestLinearDepth = linearSolution != null ? mBestSolutionDepth : -1;
// update the max depth of the optimized search to be the depth of the default time
mMaxDepthOfTree = bestLinearDepth;
//Debug.Log("Best Case Group Scenario took " + mMaxDepthOfTree + " turns to complete, needing " + (mMaxDepthOfTree - initialState.Prob.NationBlueprint.NumCitiesRemaining) + " turns to heal");
// reset search variables for the optimized search
mPruneSolutions = optimize;
mOpenLeafs.Clear();
mBestSolution = null;
mBestPartialSolution = null;
mOpenLeafs.AddLast(initialState);
// search for parallel attack strategy solutions
while (mOpenLeafs.Count > 0)
{
SearchState pop = mOpenLeafs.Last.Value;
mOpenLeafs.RemoveLast();
Search(pop, false);
}
// Record optimized Solution
InvasionSolution parallelSolution = null;
if (mBestSolution == null)
{
parallelSolution = ToSolution(mBestPartialSolution, mInitialArmy, mInitialNation);
}
else
{
parallelSolution = mBestSolution;
}
int bestOptimizedDepth = parallelSolution != null ? mBestSolutionDepth : -1;
return(new SearchResults(mNumLeafsCreated, mNumSolutionsFound,
linearSolution, parallelSolution));
}
