private List<Board> solve(Board initial) { Board twin = initial.twin(); MinPQ<SearchNode> mainQueue = new MinPQ<>(); MinPQ<SearchNode> twinQueue = new MinPQ<>(); mainQueue.insert(new SearchNode(initial, 0, null)); twinQueue.insert(new SearchNode(twin, 0, null)); while (true) { SearchNode mainSearch = mainQueue.delMin(); SearchNode twinSearch = twinQueue.delMin(); if (mainSearch.board.isGoal()) { return retraceSteps(mainSearch); } if (twinSearch.board.isGoal()) { return null; } for (Board board : mainSearch.board.neighbors()) { SearchNode mainPrevious = mainSearch.previous; if (mainPrevious == null || !board.equals(mainPrevious.board)) { mainQueue.insert(new SearchNode(board, mainSearch.moves + 1, mainSearch)); } } for (Board board : twinSearch.board.neighbors()) { SearchNode twinPrevious = twinSearch.previous; if (twinPrevious == null || !board.equals(twinPrevious.board)) { twinQueue.insert(new SearchNode(board, twinSearch.moves + 1, twinSearch)); } } } }
public static void main(String[] args) { int M = Integer.parseInt(args[0]); MinPQ<Transaction> pq = new MinPQ<>(M + 1); while (StdIn.hasNextLine()) { pq.insert(new Transaction(StdIn.readLine())); if (pq.size() > M) { pq.delMin(); } } Stack<Transaction> stack = new Stack<Transaction>(); while (!pq.isEmpty()) stack.push(pq.delMin()); for (Transaction t : stack) StdOut.println(); }
public LazyPrimMST(EdgeWeightedGraph G) { pq = new MinPQ<Edge>(G.E()); mst = new Queue<Edge>(); marked = new boolean[G.V()]; visit(G, 0); while (!pq.isEmpty()) { Edge e = pq.delMin(); int v = e.either(); int w = e.other(v); if (marked[v] && marked[w]) continue; mst.enqueue(e); if (!marked[v]) visit(G, v); else visit(G, w); } }
public static void main(String[] args) { WeightedQuickUnionUF uf = new WeightedQuickUnionUF(10); MinPQ<String> minPQ = new MinPQ<>(17, new Prob1().new myComparator()); String prob = "F-A 16 G-A 13 B-A 3 C-B 6 H-B 5 G-B 2 C-D 12 C-I 9 C-H 1 D-I 14 J-D 8 D-E 7 J-E 17 F-G 15 G-H 4 I-H 11 I-J 10"; String[] temp = prob.trim().split("\\s+"); for (int i = 0; i < temp.length; i += 2) { String record = temp[i] + "," + temp[i + 1]; minPQ.insert(record); } int sizeOfMST = 0; while (!minPQ.isEmpty() && sizeOfMST <= 9) { String minEdgeStr = minPQ.delMin(); String[] vertexStr = minEdgeStr.split(",")[0].split("-"); int v = vertexStr[0].charAt(0) - 'A'; int w = vertexStr[1].charAt(0) - 'A'; if (!uf.connected(v, w)) { uf.union(v, w); System.out.println(minEdgeStr); sizeOfMST++; } } }
// the sweep-line algorithm public static void main(String[] args) { int N = Integer.parseInt(args[0]); int INFINITY = Integer.MAX_VALUE; // -INFINITY is second smallest integer // generate N random h-v segments SegmentHV[] segments = new SegmentHV[N]; for (int i = 0; i < N; i++) { int x1 = (int) (Math.random() * 10); int x2 = x1 + (int) (Math.random() * 3); int y1 = (int) (Math.random() * 10); int y2 = y1 + (int) (Math.random() * 5); if (Math.random() < 0.5) segments[i] = new SegmentHV(x1, y1, x1, y2); else segments[i] = new SegmentHV(x1, y1, x2, y1); System.out.println(segments[i]); } System.out.println(); // create events MinPQ<Event> pq = new MinPQ<Event>(); for (int i = 0; i < N; i++) { if (segments[i].isVertical()) { Event e = new Event(segments[i].x1, segments[i]); pq.insert(e); } else if (segments[i].isHorizontal()) { Event e1 = new Event(segments[i].x1, segments[i]); Event e2 = new Event(segments[i].x2, segments[i]); pq.insert(e1); pq.insert(e2); } } // run sweep-line algorithm RangeSearch<SegmentHV> st = new RangeSearch<SegmentHV>(); while (!pq.isEmpty()) { Event e = pq.delMin(); int sweep = e.time; SegmentHV segment = e.segment; // vertical segment if (segment.isVertical()) { // a bit of a hack here - use infinity to handle degenerate intersections SegmentHV seg1 = new SegmentHV(-INFINITY, segment.y1, -INFINITY, segment.y1); SegmentHV seg2 = new SegmentHV(+INFINITY, segment.y2, +INFINITY, segment.y2); Iterable<SegmentHV> list = st.range(seg1, seg2); for (SegmentHV seg : list) { System.out.println("Intersection: " + segment); System.out.println(" " + seg); } } // next event is left endpoint of horizontal h-v segment else if (sweep == segment.x1) { st.add(segment); } // next event is right endpoint of horizontal h-v segment else if (sweep == segment.x2) { st.remove(segment); } } }