//getNextStep determines the step the computer will make given the current status
//of the board and the difficulty level
public static State getNextStep(State s, int diff)
{
List<State> possible = new List<State>();
List<Tree> tree = new List<Tree>();
for (int i = 8; i < 16; i++)
{
s.addStep(i, possible, false);
}
foreach (State st in possible)
{
Tree fresh = new Tree(st);
tree.Add(fresh);
}
//for different difficulty level(lvl3 is disabled due to memory constraint)
switch (diff)
{
case 1:
foreach (Tree t in tree)
{
t.populate(2);
}
break;
case 2:
foreach (Tree t in tree)
{
t.populate(4);
}
break;
case 3:
foreach (Tree t in tree)
{
t.populate(6);
}
break;
default:
break;
}
foreach (Tree t in tree)
{
t.calc();
}
int max = -2000;
int refer = 0;
int num = 0;
int c = 0;
foreach (Tree t in tree)
{
if (t.value > max)
{
max = t.value;
refer = num;
}
if (t.value == max)
{
c++;
}
num++;
}
if (c != 1)
{
num = 0;
foreach (Tree t in tree)
{
if(t.value == max)
{
t.state.eval();
if (t.state.value > max)
{
max = t.state.value;
refer = num;
}
}
num++;
}
}
if (possible.Count == 0) return null;
//find the most yielding step and return its state
return possible[refer];
}
//To generate all the possible states in the future given the current state and how far into the future(count)
public void populate(int count)
{
if (count == 0) return;
List<State> temp = new List<State>();
if (height % 2 != 0)
{
for (int i = 0; i < 8; i++)
{
state.addStep(i, temp, false);
}
}
else
{
for (int i = 8; i < 16; i++)
{
state.addStep(i, temp, false);
}
}
if (temp.Count == 0)
{
this.value = height % 2 == 0 ? -1000 : 1000;
}
foreach (State st in temp)
{
Tree fresh = new Tree(st);
fresh.height = this.height + 1;
next.Add(fresh);
}
foreach (Tree t in next)
{
t.populate(count - 1);
}
}