-
Notifications
You must be signed in to change notification settings - Fork 0
/
BFSPathfinder.java
40 lines (30 loc) · 1.17 KB
/
BFSPathfinder.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
package com.navigation.pathfinder.pathfinding;
import com.navigation.pathfinder.graph.Edge;
import com.navigation.pathfinder.graph.Graph;
import com.navigation.pathfinder.graph.Vertex;
import com.navigation.pathfinder.path.PathSummaryCreator;
import java.util.ArrayDeque;
import java.util.HashMap;
public class BFSPathfinder implements PathfindingStrategy {
private static final PathSummaryCreator pathSummaryCreator = new PathSummaryCreator();
@Override
public PathSummary findPath(Vertex start, Vertex end, Graph graph) {
var predecessorTree = new HashMap<Vertex, Edge>();
predecessorTree.put(start, null);
var queue = new ArrayDeque<Vertex>();
queue.add(start);
while (!queue.isEmpty()) {
var curr = queue.poll();
if (curr.equals(end)) {
return pathSummaryCreator.createUnidirectionalPath(start, end, predecessorTree);
}
for (var edge : graph.getVertexEdges(curr)) {
if (!predecessorTree.containsKey(edge.getTo())) {
predecessorTree.put(edge.getTo(), edge);
queue.add(edge.getTo());
}
}
}
return pathSummaryCreator.createUnidirectionalPath(start, end, predecessorTree);
}
}