From 421ec17af505299b3b213fe5d4d7d4efe6363a0a Mon Sep 17 00:00:00 2001
From: Sugam Adhikari <sugam.adhiakri123@gmail.com>
Date: Sun, 30 Aug 2020 17:30:09 +0545
Subject: [PATCH] Fixed PriorityQueue Logic

I have added a class at the end for the comparator to fulfill the comparison needed to arrange the nodes in the priority queue.
---
 src/roadgraph/MapGraph.java | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/roadgraph/MapGraph.java b/src/roadgraph/MapGraph.java
index 0437c8f..c0d0e3d 100644
--- a/src/roadgraph/MapGraph.java
+++ b/src/roadgraph/MapGraph.java
@@ -322,6 +322,7 @@ private List<GeographicPoint> searchOnWeightedGraph(GeographicPoint start, Geogr
 		MapNode endNode = pointNodeMap.get(goal);
 
 		HashMap<MapNode, MapNode> parentMap = new HashMap<MapNode, MapNode>();
+		DistanceComparator comparator = new DistanceComparator(getNumEdges(), comparator);
 		PriorityQueue<MapNode> toExplore = new PriorityQueue<MapNode>();
 		HashSet<MapNode> visited = new HashSet<MapNode>();
 
@@ -461,3 +462,19 @@ public static void main(String[] args) {
 	}
 
 }
+
+class DistanceComparator implements Comparator<MapNode>{
+	@Override
+	public int compare(MapNode a, MapNode b) {
+		double distanceA = a.getActualDistance() + a.getDistance();
+		double distanceB = b.getActualDistance() + b.getDistance();
+		
+		if(distanceA < distanceB) {
+			return -1;
+		}
+		if(distanceB < distanceA) {
+			return 1;
+		}
+		return 0;
+	}
+}