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 22:42:29
言語 Java
(openjdk 23)
結果
WA  
実行時間 -
コード長 4,316 bytes
コンパイル時間 2,525 ms
コンパイル使用メモリ 87,640 KB
実行使用メモリ 72,192 KB
平均クエリ数 197.21
最終ジャッジ日時 2024-07-16 17:43:10
合計ジャッジ時間 13,707 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge1
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 WA * 1
other AC * 3 WA * 24
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.List;

public class Main {

  private static void solve() {
    int n = ni();

    List<Integer> cand = new ArrayList<>();
    for (int i = 0; i < n; i ++) {
      cand.add(i);
    }
    
    int[] from = new int[2000];
    int[] to = new int[2000];
    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(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, ptr);
    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(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(cand2.get(0));
  }

  static int[][] packD(int n, int[] from, int[] to, int m) {
    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 < m; i++) {
      g[from[i]][--p[from[i]]] = to[i];
    }
    return g;
  }

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

  private static void ans(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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