コード例 #1
0
ファイル: Multiway.java プロジェクト: sunz7/algorithmCourse
  // merge together the sorted input streams and write the sorted result to standard output
  private static void merge(In[] streams) {
    int N = streams.length;
    IndexMinPQ<String> pq = new IndexMinPQ<String>(N);
    for (int i = 0; i < N; i++) if (!streams[i].isEmpty()) pq.insert(i, streams[i].readString());

    // Extract and print min and read next from its stream.
    while (!pq.isEmpty()) {
      StdOut.print(pq.minKey() + " ");
      int i = pq.delMin();
      if (!streams[i].isEmpty()) pq.insert(i, streams[i].readString());
    }
    StdOut.println();
  }
コード例 #2
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 // relax edge e and update pq if changed
 private void relaxC(Route r, int v) {
   City city2 = r.other(cities[v]);
   int w = city2.id() - 1;
   if (costTo[w] > costTo[v] + r.price()) {
     costTo[w] = costTo[v] + r.price();
     edgeTo[w] = r;
     if (costPQ.contains(w)) costPQ.change(w, costTo[w]);
     else costPQ.insert(w, costTo[w]);
   }
 }
コード例 #3
0
	private void relax(EdgeWeightedDigraph G ,int v){
		for(DirectedEdge e:G.adj(V)){
			int w = e.to();
			if(distTo[w]>distTo[v]+e.weight()){
				distTo[w] = distTo[v]+e.weight();
				edgeTo[w] = e;
				if(pq.contains(w)) pq.change(w,distTo[w]);
				else pq.insert(w,distTo[w]);
			}
		}
	}
コード例 #4
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 private void relaxD(Route r, int v) {
   // relax edge e and update pq if changed
   City city2 = r.other(cities[v]);
   int w = city2.id() - 1;
   if (distTo[w] > distTo[v] + r.distance()) {
     distTo[w] = distTo[v] + r.distance();
     edgeTo[w] = r;
     if (pq.contains(w)) pq.change(w, distTo[w]);
     else pq.insert(w, distTo[w]);
   }
 }
コード例 #5
0
	public DijkstraSP(EdgeWeightedDigraph G , int s){
		edgeTo =new DirectedEdge[G.V()];
		distTo =new double[G.V()];
		pq = new  IndexMinPQ<Double>(G.V());

		for(int v = 0 ; v < G.V() ; v++) distTo[v] = Double.POSITIVE_INFINITY;
		distTo[s]=0;
		pq.insert(s,0.0);
		while(!pq.isEmpty()){
			relax(G,pq.delMin());
		}
	}
コード例 #6
0
ファイル: PrimMST.java プロジェクト: bmpasini/algorithms
  public PrimMST(EdgeWeightedGraph G) {
    edgeTo = new Edge[G.V()];
    distTo = new double[G.V()];
    marked = new boolean[G.V()];

    for (int v = 0; v < G.V(); v++) distTo[v] = Double.POSITIVE_INFINITY;
    pq = new IndexMinPQ<Double>(G.V());

    distTo[0] = 0.0;
    pq.insert(0, 0.0); // Initialize pq with 0, weight 0.
    while (!pq.isEmpty()) visit(G, pq.delMin()); // Add closest vertex to tree.
  }
コード例 #7
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 private void prim(int s, StringBuilder sb) {
   distTo[s] = 0;
   pq.insert(s, distTo[s]);
   while (!pq.isEmpty()) {
     int v = pq.delMin();
     if (v != s) {
       Route r = edgeTo[v];
       String str = String.format("%s, %s : %d\n", r.fst(), r.snd(), r.distance());
       sb.append(str);
     }
     scan(v);
   }
 }
コード例 #8
0
ファイル: MyPrimMST.java プロジェクト: dogeyes/Algorithm
 public void visit(int v) {
   marked[v] = true;
   for (Edge e : G.adj(v)) {
     int w = e.other(v);
     if (marked[w]) continue;
     if (disTo[w] > e.weight()) {
       disTo[w] = e.weight();
       if (!pq.contains(w)) {
         pq.insert(w, e.weight());
       } else pq.changeKey(w, e.weight());
       edgeTo[w] = v;
     }
   }
 }
コード例 #9
0
ファイル: PrimMST.java プロジェクト: bmpasini/algorithms
 private void visit(EdgeWeightedGraph G, int v) // Add v to tree; update data structures.
     {
   marked[v] = true;
   for (Edge e : G.adj(v)) {
     int w = e.other(v);
     if (marked[w]) continue; // v-w is ineligible.
     if (e.weight() < distTo[w]) // Edge e is new best connection from tree to w.
     {
       edgeTo[w] = e;
       distTo[w] = e.weight();
       if (pq.contains(w)) pq.change(w, distTo[w]);
       else pq.insert(w, distTo[w]);
     }
   }
 }
コード例 #10
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 private void scan(int v) {
   marked[v] = true;
   for (Route r : adj[v]) {
     int w = r.other(cities[v]).id() - 1; // index of other city in route
     if (marked[w]) {
       continue; // v-w is obsolete edge
     }
     if (r.distance() < distTo[w]) {
       distTo[w] = r.distance();
       edgeTo[w] = r;
       if (pq.contains(w)) {
         pq.change(w, distTo[w]);
       } else {
         pq.insert(w, distTo[w]);
       }
     }
   }
 }
コード例 #11
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 // Option 4
 public void shortestByCost(String c1, String c2) {
   System.out.println("SHORTEST COST PATH from " + c1 + " to " + c2);
   System.out.println("--------------------------------------------------------");
   City city1 = null;
   City city2 = null;
   for (int i = 0; i < numCities; i++) {
     if (cities[i].name().equals(c1)) {
       city1 = cities[i];
     }
     if (cities[i].name().equals(c2)) {
       city2 = cities[i];
     }
   }
   if (c1.equals(c2) || city1 == null || city2 == null) {
     System.out.println("Invalid city choice(s)");
     return;
   }
   costTo = new double[numCities];
   edgeTo = new Route[numCities];
   for (int i = 0; i < numCities; i++) costTo[i] = Double.POSITIVE_INFINITY;
   costTo[city1.id() - 1] = 0;
   // relax vertices in order of distance from s
   costPQ = new IndexMinPQ<Double>(numCities);
   costPQ.insert(city1.id() - 1, costTo[city1.id() - 1]);
   while (!costPQ.isEmpty()) {
     int v = costPQ.delMin();
     for (Route r : adj[v]) relaxC(r, v);
   }
   if (costTo[city2.id() - 1] == Double.POSITIVE_INFINITY) {
     System.out.println("No path");
     return;
   }
   System.out.printf("Shortest cost from %s to %s is %.2f\n", c1, c2, costTo[city2.id() - 1]);
   System.out.println("Path with edges (in reverse order):");
   City currCity = city2;
   for (Route r = edgeTo[city2.id() - 1]; r != null; r = edgeTo[currCity.id() - 1]) {
     System.out.print(currCity + " " + r.price() + " ");
     currCity = r.other(currCity);
   }
   System.out.println(currCity);
 }
コード例 #12
0
ファイル: Airline.java プロジェクト: techbeck/School-Projects
 // Option 3
 public void shortestByDistance(String c1, String c2) {
   System.out.println("SHORTEST DISTANCE PATH from " + c1 + " to " + c2);
   System.out.println("--------------------------------------------------------");
   City city1 = null;
   City city2 = null;
   for (int i = 0; i < numCities; i++) {
     if (cities[i].name().equals(c1)) {
       city1 = cities[i];
     }
     if (cities[i].name().equals(c2)) {
       city2 = cities[i];
     }
   }
   if (c1.equals(c2) || city1 == null || city2 == null) {
     System.out.println("Invalid city choice(s)");
     return;
   }
   distTo = new int[numCities];
   edgeTo = new Route[numCities];
   for (int i = 0; i < numCities; i++) distTo[i] = Integer.MAX_VALUE;
   distTo[city1.id() - 1] = 0;
   // relax vertices in order of distance from s
   pq = new IndexMinPQ<Integer>(numCities);
   pq.insert(city1.id() - 1, distTo[city1.id() - 1]);
   while (!pq.isEmpty()) {
     int v = pq.delMin();
     for (Route r : adj[v]) relaxD(r, v);
   }
   if (distTo[city2.id() - 1] == Integer.MAX_VALUE) {
     System.out.println("No path");
     return;
   }
   System.out.printf("Shortest distance from %s to %s is %d\n", c1, c2, distTo[city2.id() - 1]);
   System.out.println("Path with edges (in reverse order):");
   City currCity = city2;
   for (Route r = edgeTo[city2.id() - 1]; r != null; r = edgeTo[currCity.id() - 1]) {
     System.out.print(currCity + " " + r.distance() + " ");
     currCity = r.other(currCity);
   }
   System.out.println(currCity);
 }