結果

問題 No.850 企業コンテスト2位
コンテスト
ユーザー hiromi_ayase
提出日時 2019-07-06 22:55:53
言語 Java
(openjdk 23)
結果
AC  
実行時間 192 ms / 2,000 ms
コード長 5,601 bytes
コンパイル時間 2,995 ms
コンパイル使用メモリ 93,384 KB
実行使用メモリ 71,096 KB
平均クエリ数 200.11
最終ジャッジ日時 2024-07-16 17:42:17
合計ジャッジ時間 9,052 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 27
権限があれば一括ダウンロードができます

ソースコード

diff # 

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
import java.util.function.BiFunction;
import java.util.function.Consumer;

public class Main {
  private static final boolean DEBUG = false;

  private static void solve() {
    if (DEBUG) {
      Random gen = new Random();

      for (int t = 0; t < 1000; t++) {
        int[] a = new int[gen.nextInt(299) + 2];
        for (int i = 0; i < a.length; i++) {
          a[i] = i + 1;
        }
        for (int i = 0; i < a.length; i++) {
          int j = gen.nextInt(a.length);

          int tmp = a[i];
          a[i] = a[j];
          a[j] = tmp;
        }
        Main.a = a;
        Main.cnt = 0;
        solve(Main.a.length, (x, y) -> askTest(x, y), x -> ansTest(x));
      }
    } else {
      solve(ni(), (x, y) -> askIO(x, y), x -> ansIO(x));
    }
  }

  private static void solve(int n, BiFunction<Integer, Integer, Boolean> ask,
      Consumer<Integer> ans) {

    List<Integer> cand = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      cand.add(i);
    }

    int[] from = new int[n - 1];
    int[] to = new int[n - 1];
    int ptr = 0;

    while (cand.size() > 1) {
      List<Integer> next = new ArrayList<>();
      for (int i = 0; i < cand.size() - 1; i += 2) {
        int u = cand.get(i);
        int v = cand.get(i + 1);
        if (ask.apply(u, v)) {
          next.add(u);
          from[ptr] = u;
          to[ptr] = v;
        } else {
          next.add(v);
          from[ptr] = v;
          to[ptr] = u;
        }
        ptr++;
      }
      if (cand.size() % 2 == 1) {
        next.add(cand.get(cand.size() - 1));
      }
      cand = next;
    }

    int[][] g = packD(n, from, to);
    List<Integer> cand2 = new ArrayList<>();
    for (int v : g[cand.get(0)]) {
      cand2.add(v);
    }

    while (cand2.size() > 1) {
      List<Integer> next = new ArrayList<>();
      for (int i = 0; i < cand2.size() - 1; i += 2) {
        int u = cand2.get(i);
        int v = cand2.get(i + 1);
        if (ask.apply(u, v)) {
          next.add(u);
        } else {
          next.add(v);
        }
        ptr++;
      }
      if (cand2.size() % 2 == 1) {
        next.add(cand2.get(cand2.size() - 1));
      }
      cand2 = next;
    }

    ans.accept(cand2.get(0));
  }

  static int[][] packD(int n, int[] from, int[] to) {
    int[][] g = new int[n][];
    int[] p = new int[n];
    for (int f : from)
      p[f]++;
    for (int i = 0; i < n; i++)
      g[i] = new int[p[i]];
    for (int i = 0; i < from.length; i++) {
      g[from[i]][--p[from[i]]] = to[i];
    }
    return g;
  }


  static int[] a;

  private static int cnt = 0;
  private static boolean askTest(int x, int y) {
    cnt++;
    for (int v : a) {
      if (v == x + 1)
        return true;
      if (v == y + 1)
        return false;
    }
    return false;
  }

  private static void ansTest(int x) {
    if (a[1] != x + 1) {
      throw new RuntimeException(x + 1 + ":" + Arrays.toString(a));
    }
    System.err.println(cnt);
  }


  private static boolean askIO(int x, int y) {
    out.println("? " + (x + 1) + " " + (y + 1));
    out.flush();
    return ni() == x + 1;
  }

  private static void ansIO(int x) {
    out.println("! " + (x + 1));
  }

  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = args.length > 0 ? args[0] : null;
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

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

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}
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