// jai mata di
private void astar(char[][] maze) {
// HashMap for storing frontier for efficient search
int nodes_expanded = 0;
HashMap<PacPoint, Integer> map = new HashMap<PacPoint, Integer>();
PriorityQueue<PacPoint> frontier = new PriorityQueue<PacPoint>();
frontier.add(start);
map.put(start, getFunctionValue(start));
int M = maze.length;
int N = maze[0].length;
while (!frontier.isEmpty()) {
PacPoint current = frontier.remove();
map.remove(current);
// check if it is a .
// check if you have reached a goal
if (checkGoal(current)) {
System.out.println("Reached The Goal !!");
System.out.println("Number of Nodes Expanded : " + nodes_expanded);
print_solution(current, maze);
return;
}
nodes_expanded++;
// Move Right
if (current.p.y + 1 < N && current.p.x < M && maze[current.p.x][current.p.y + 1] != '%') {
PacPoint next = new PacPoint(current.p.x, current.p.y + 1);
// copy goals from current
for (int i = 0; i < current.goals.size(); i++) {
next.goals.add(current.goals.get(i));
}
if (next.goals.contains(next.p)) next.goals.remove(next.p);
boolean shouldAdd = true;
next.parent = current;
next.pathCost = current.pathCost + 1;
next.heuristic = computeHeuristic(next.p, current.goals);
if (checkIfExistsHigherCost(next, map)) {
frontier.remove(next);
map.remove(next);
} else if (checkIfExistsLowerCost(next, map)) {
shouldAdd = false;
}
if (shouldAdd) {
frontier.add(next);
map.put(next, getFunctionValue(next));
}
}
// Move Left
if (current.p.y - 1 >= 0 && current.p.x < M && maze[current.p.x][current.p.y - 1] != '%') {
PacPoint next = new PacPoint(current.p.x, current.p.y - 1);
// copy goals from current
for (int i = 0; i < current.goals.size(); i++) {
next.goals.add(current.goals.get(i));
}
if (next.goals.contains(next.p)) next.goals.remove(next.p);
boolean shouldAdd = true;
next.parent = current;
next.pathCost = current.pathCost + 1;
next.heuristic = computeHeuristic(next.p, current.goals);
if (checkIfExistsHigherCost(next, map)) {
frontier.remove(next);
map.remove(next);
} else if (checkIfExistsLowerCost(next, map)) {
shouldAdd = false;
}
if (shouldAdd) {
frontier.add(next);
map.put(next, getFunctionValue(next));
}
}
// Move Up
if (current.p.x - 1 >= 0 && current.p.y < N && maze[current.p.x - 1][current.p.y] != '%') {
PacPoint next = new PacPoint(current.p.x - 1, current.p.y);
// copy goals from current
for (int i = 0; i < current.goals.size(); i++) {
next.goals.add(current.goals.get(i));
}
if (next.goals.contains(next.p)) next.goals.remove(next.p);
boolean shouldAdd = true;
next.parent = current;
next.pathCost = current.pathCost + 1;
next.heuristic = computeHeuristic(next.p, current.goals);
if (checkIfExistsHigherCost(next, map)) {
frontier.remove(next);
map.remove(next);
} else if (checkIfExistsLowerCost(next, map)) {
shouldAdd = false;
}
if (shouldAdd) {
frontier.add(next);
map.put(next, getFunctionValue(next));
}
}
// Move down
if (current.p.x + 1 < M && current.p.y < N && maze[current.p.x + 1][current.p.y] != '%') {
PacPoint next = new PacPoint(current.p.x + 1, current.p.y);
// copy goals from current
for (int i = 0; i < current.goals.size(); i++) {
next.goals.add(current.goals.get(i));
}
if (next.goals.contains(next.p)) next.goals.remove(next.p);
boolean shouldAdd = true;
next.parent = current;
next.pathCost = current.pathCost + 1;
next.heuristic = computeHeuristic(next.p, current.goals);
if (checkIfExistsHigherCost(next, map)) {
frontier.remove(next);
map.remove(next);
} else if (checkIfExistsLowerCost(next, map)) {
shouldAdd = false;
}
if (shouldAdd) {
frontier.add(next);
map.put(next, getFunctionValue(next));
}
}
}
}
