private void dfs(Digraph G, int v) {
marked[v] = true;
preorder[v] = pre++;
stack1.push(v);
stack2.push(v);
for (int w : G.adj(v)) {
if (!marked[w]) dfs(G, w);
else if (id[w] == -1) {
while (preorder[stack2.peek()] > preorder[w]) stack2.pop();
}
}
// found strong component containing v
if (stack2.peek() == v) {
stack2.pop();
int w;
do {
w = stack1.pop();
id[w] = count;
} while (w != v);
count++;
}
}
/**
* Reads a sequence of transactions from standard input; takes a command-line integer M; prints to
* standard output the M largest transactions in descending order.
*/
public static void main(String[] args) {
int M = Integer.parseInt(args[0]);
MinPQ<Transaction> pq = new MinPQ<Transaction>(M + 1);
while (StdIn.hasNextLine()) {
// Create an entry from the next line and put on the PQ.
String line = StdIn.readLine();
Transaction transaction = new Transaction(line);
pq.insert(transaction);
// remove minimum if M+1 entries on the PQ
if (pq.size() > M) pq.delMin();
} // top M entries are on the PQ
// print entries on PQ in reverse order
Stack<Transaction> stack = new Stack<Transaction>();
for (Transaction transaction : pq) stack.push(transaction);
for (Transaction transaction : stack) StdOut.println(transaction);
}
/**
* Returns the vertices in reverse postorder.
*
* @return the vertices in reverse postorder, as an iterable of vertices
*/
public Iterable<Integer> reversePost() {
Stack<Integer> reverse = new Stack<Integer>();
for (int v : postorder) reverse.push(v);
return reverse;
}