Submission #309916

#	Time	Username	Problem	Language	Result	Execution time	Memory
309916		ijxjdjd	Power Plant (JOI20_power)	Java	100 / 100	1314 ms	68452 KiB

power

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

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

    static class powersol {
        char[] s;
        int[][] adj;
        int ans = 0;

        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt();
            int[] U = new int[N - 1];
            int[] V = new int[N - 1];
            for (int i = 0; i < N - 1; i++) {
                U[i] = in.nextInt() - 1;
                V[i] = in.nextInt() - 1;
            }
            adj = DefaultTree.packU(N, U, V);
            s = in.next().toCharArray();
            dfs(0, 0);
            out.println(ans);
        }

        int dfs(int n, int p) {
            int mx = 0;
            int tot = 0;
            for (int e : adj[n]) {
                if (e != p) {
                    int a = dfs(e, n);
                    mx = Math.max(mx, a);
                    tot += a;
                }
            }
            ans = Math.max(ans, tot - (s[n] == '1' ? 1 : 0));
            if (s[n] == '1') {
                ans = Math.max(ans, mx + 1);
            }
            if (s[n] == '1') {
                return Math.max(1, tot - 1);
            }
            return tot;
        }

    }

    static class DefaultTree {
        DefaultTree.Node[] tree;
        int K;
        int[][] lift;
        int[] tin;
        int[] tout;

        public DefaultTree(int N) {
            tree = new DefaultTree.Node[N];
            K = (int) Math.ceil(Math.log(N) / Math.log(2)) + 1;
            lift = new int[N][K];
            tin = new int[N];
            tout = new int[N];
            for (int i = 0; i < N; i++) {
                tree[i] = new DefaultTree.Node();
            }
        }

        public static int[][] packU(int N, int[] from, int[] to) {
            //undirected
            int[][] adj = new int[N][];
            int[] cntFrom = new int[N];
            for (int i = 0; i < from.length; i++) {
                cntFrom[from[i]]++;
                cntFrom[to[i]]++;
            }
            for (int i = 0; i < N; i++) {
                adj[i] = new int[cntFrom[i]];
            }
            for (int i = 0; i < from.length; i++) {
                adj[from[i]][--cntFrom[from[i]]] = to[i];
                adj[to[i]][--cntFrom[to[i]]] = from[i];
            }
            return adj;
        }

        static class Node {
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
}

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 53 / 53