Submission #32782185

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Source Code Expand

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.TreeSet;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        EReversi solver = new EReversi();
        solver.solve(1, in, out);
        out.close();
    }

    static class EReversi {
        List<Integer>[] graph;
        int[] subtree;
        boolean[] white;
        int[] parent;

        void dfs(int u, int p) {
            parent[u] = p;
            subtree[u] = white[u] ? 1 : 0;
            for (int v : graph[u]) {
                if (v != p) {

                    dfs(v, u);
                    subtree[u] ^= subtree[v];
                }
            }
        }

        public void solve(int testNumber, FastScanner in, PrintWriter out) {
            int n = in.nextInt();
            graph = Utils.listArray(n);
            for (int i = 0; i < n - 1; i++) {
                int from = in.nextInt() - 1, to = in.nextInt() - 1;
                graph[from].add(to);
                graph[to].add(from);
            }
            white = new boolean[n];
            String colors = in.next();
            for (int i = 0; i < n; i++) {
                white[i] = colors.charAt(i) == 'W';
            }
            subtree = new int[n];
            parent = new int[n];
            dfs(0, -1);
            if (subtree[0] == 0) {
                out.println("-1");
                return;
            }
            boolean[] used = new boolean[n];
            TreeSet<Integer> canUse = new TreeSet<>();
            for (int i = 0; i < n; i++) {
                if (white[i] && subtree[i] == 1) {
                    canUse.add(i);
                }
            }

            for (int IT = 0; IT < n; IT++) {
                int vertex = canUse.pollFirst();
                used[vertex] = true;
                out.print((vertex + 1) + " ");
                for (int neighbor : graph[vertex]) {
                    if (!used[neighbor]) {
                        if (white[neighbor] && subtree[neighbor] == 1) {
                            canUse.remove(neighbor);
                        }
                        white[neighbor] ^= true;
                        if (neighbor != parent[vertex]) {
                            subtree[neighbor] ^= 1;
                        }
                        if (white[neighbor] && subtree[neighbor] == 1) {
                            canUse.add(neighbor);
                        }
                    }
                }
            }
            out.println();
        }

    }

    static class Utils {
        public static <T> List<T>[] listArray(int size) {
            List<T>[] result = new List[size];
            for (int i = 0; i < size; i++) {
                result[i] = new ArrayList<>();
            }
            return result;
        }

    }

    static class FastScanner {
        public BufferedReader br;
        public StringTokenizer st;

        public FastScanner(InputStream in) {
            br = new BufferedReader(new InputStreamReader(in));
        }

        public FastScanner(String fileName) {
            try {
                br = new BufferedReader(new FileReader(fileName));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public String next() {
            while (st == null || !st.hasMoreElements()) {
                String line = null;
                try {
                    line = br.readLine();
                } catch (IOException e) {
                    throw new UnknownError();
                }
                if (line == null) {
                    throw new UnknownError();
                }
                st = new StringTokenizer(line);
            }
            return st.nextToken();
        }

    }
}

Submission Info

Compile Error

Note: ./Main.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

Judge Result