Hey guys, So I'm trying write a dijstra's implementation in java. First off, here is the algorith:

I followed someone else's psuedocode very closely but for whatever reason, my edge[] array is just full of null data, which means I can't actually return the shortest path. Any ideas on why that's happening/how to fix it? Maybe I'm not understanding dijstra's correctly. Anyway, thanks for your help.package lab3; import java.util.HashMap; import java.util.Stack; /** * Compute shortest paths in a graph. * * Your constructor should compute the actual shortest paths and * maintain all the information needed to reconstruct them. The * returnPath() function should use this information to return the * appropriate path of edge ID's from the start to the given end. * * Note that the start and end ID's should be mapped to vertices using * the graph's get() function. */ class ShortestPaths { Multigraph graph; final int INF = Integer.MAX_VALUE; PriorityQueue<Integer> Q; int n; int dist[]; Handle handles[]; Edge edge[]; /** * Constructor */ public ShortestPaths(Multigraph G, int startId) { Q = new PriorityQueue<Integer>(); graph = G; n = graph.nVertices(); dist = new int [n]; edge = new Edge [n]; handles = new Handle[n]; for (int i = 0; i<n; i++){ dist[i] = INF; } dist[startId] = 0; Handle h = Q.insert(startId, dist[startId]); handles[startId] = h; Q = new PriorityQueue<Integer>(); while (!Q.isEmpty()){ Vertex v = graph.get(Q.min()); Q.extractMin(); while (v.adj().hasNext()){ relax(v.adj().next()); } } } private void relax(Edge e) { Handle h; int v = e.from().id(); int w = e.to().id(); if (dist[w] > dist[v] + e.weight()) { dist[w] = dist[v] + e.weight(); edge[w] = e; if (handles[w].getIndex() != -1){ Q.decreaseKey(handles[w], dist[w]); } else{ h = Q.insert(w, dist[w]); handles[w] = h; } } } /** * Calculates the list of edge ID's forming a shortest path from the start * vertex to the specified end vertex. * * @return the array */ public int[] returnPath(int endId) { int c = 0; int[] path = new int[edge.length]; for (Edge e = edge[endId]; e != null; e = edge[e.from().id()]) { path[c] = e.id(); c++; } return path; } }