I got WA#1 :(
What's wrong bros?

===============================================================
static int speakerCount = 0;

    static void solve() throws IOException {
        final int N = nextInt();

        // graph[i][j] = true: i-th is parent of j-th
        final boolean[][] graph = new boolean[N + 1][N + 1];

        for (int line = 1; line <= N; line++) {
            int parent = nextInt();

            if (parent == 0) {
                continue;
            }

            int child = nextInt();
            while (0 < child) {
                graph[parent][child] = true;

                child = nextInt();
            }
        }

        StringBuilder speakerList = new StringBuilder();
        final boolean[] visitedNodes = new boolean[N + 1];

        while (speakerCount < N) {
            for (int node = 1; node <= N; node++) {
                if (!visitedNodes[node]) {
                    visit(node, visitedNodes, speakerList, graph);

                    break;
                }
            }
        }

        out.println(speakerList.toString().trim());
    }

    private static void visit(int node, boolean[] visitedNodes,
            StringBuilder speakerList, boolean[][] graph) {

        // Stop if marked
        if (visitedNodes[node]) {
            return;
        }

        // Marked
        visitedNodes[node] = true;

        // Visit each child
        for (int child = 1; child < visitedNodes.length; child++) {
            if (graph[node][child]) {
                visit(child, visitedNodes, speakerList, graph);
            }
        }

        speakerList.insert(0, node + " ");
        speakerCount++;
    }

Edited by author 23.05.2014 15:48

I think the problem is that a children could have more than 1 parent - and here you have to check if all of his parents have been printed. If you can't find the solution yourself - write and I will tell you a way.

P.S. Other people say that "One of the lines in test 4 has trailing space. This old problem was designed for Pascal/C++, such inputs treated as a bad style nowadays."
I don't know what this means, but first check if this is the problem!

Edited by author 07.01.2015 04:12