public Boolean insert(Spot x)
{
if (x == null)
{
return(false);
}
if (length == 0)
{
first = x;
last = x;
}
else
{
if (x.f <= first.f)
{
first.previous = x;
x.next = first;
x.previous = null;
first = x;
}
else
{
Spot tmp = first.next;
while (tmp != null)
{
if (x.f <= tmp.f)
{
x.previous = tmp.previous;
x.next = tmp;
tmp.previous.next = x;
tmp.previous = x;
break;
}
tmp = tmp.next;
}
if (tmp == null)
{
x.previous = last;
last.next = x;
last = x;
}
}
}
length++;
return(true);
}
static Spot[,] MakeReasonableGrid(int r, int c, int pacman_r, int pacman_c, int food_r, int food_c, String[] grid)
{
Spot[,] Grid = new Spot[r, c];
int j_index = 0;
foreach (string item in grid)
{
char[] helper = item.ToCharArray();
for (int i = 0; i < helper.Length; i++)
{
if (helper[i].ToString() == "%")
{
Grid[j_index, i] = new Spot(j_index, i, false);
continue;
}
if (helper[i].ToString() == "-")
{
Grid[j_index, i] = new Spot(j_index, i, true);
continue;
}
else
{
Grid[j_index, i] = new Spot(j_index, i, true);
}
}
j_index++;
}
for (var i = 0; i < c; i++)
{
for (var j = 0; j < r; j++)
{
if (Grid[j, i].accessible)
{
Grid[j, i].addNeighbors(Grid, c, r);
}
}
}
return(Grid);
}
public Spot getElement()
{
if (first == null)
{
return(null);
}
else
{
length--;
Spot tmp = first;
if (tmp.next == null)
{
last = null;
return(tmp);
}
else
{
first = tmp.next;
first.previous = null;
return(tmp);
}
}
}
public void update(double cost, Spot Parent)
{
parent = Parent;
g = cost;
f = g + h;
}
static void astar(int r, int c, int pacman_r, int pacman_c, int food_r, int food_c, String[] grid)
{
SimplePriorityQue openList = new SimplePriorityQue();
//List<Spot> openList = new List<Spot>();
HashSet <Spot> closedList = new HashSet <Spot>();
Spot[,] Grid = MakeReasonableGrid(r, c, pacman_r, pacman_c, food_r, food_c, grid);
var start = Grid[pacman_r, pacman_c];
var end = Grid[food_r, food_c];
openList.insert(start);
Spot current = null;
while (!openList.isEmpty())
{
current = openList.getElement();
if (!current.accessible)
{
continue;
}
if (current == end)
{
break;
}
closedList.Add(current);
foreach (var item in current.neighbors)
{
if (closedList.Contains(item))
{
continue;
}
if (!item.accessible)
{
continue;
}
double tempG = current.g + 1;
double heuristic = Math.Abs(end.I - current.I) + Math.Abs(end.J - current.J);
if (!openList.contains(item))
{
item.h = heuristic;
item.g = tempG;
item.f = item.g + item.h;
item.parent = current;
openList.insert(item);
}
else
{
Spot tmp = openList.get(item);
if (tmp.g > tempG)
{
tmp.update(tempG, current);
}
openList.insert(tmp);
}
}
}
List <Spot> path = new List <Spot>();
Spot help = current.parent;
while (help != null)
{
path.Add(help);
help = help.parent;
}
path.Reverse();
Console.WriteLine(path.Count);
foreach (var item in path)
{
Console.WriteLine(item.I + " " + item.J);
}
}