結果

問題 No.763 Noelちゃんと木遊び
ユーザー hiromi_ayasehiromi_ayase
提出日時 2018-12-13 01:45:12
言語 Java21
(openjdk 21)
結果
AC  
実行時間 366 ms / 2,000 ms
コード長 3,376 bytes
コンパイル時間 4,864 ms
コンパイル使用メモリ 81,728 KB
実行使用メモリ 78,576 KB
最終ジャッジ日時 2023-10-25 08:56:02
合計ジャッジ時間 13,203 ms
ジャッジサーバーID
（参考情報） 		judge11 / judge13
このコードへのチャレンジ
（要ログイン）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 307 ms
78,576 KB
testcase_01 AC 212 ms
59,376 KB
testcase_02 AC 309 ms
63,592 KB
testcase_03 AC 252 ms
60,336 KB
testcase_04 AC 223 ms
59,548 KB
testcase_05 AC 246 ms
60,460 KB
testcase_06 AC 366 ms
64,468 KB
testcase_07 AC 335 ms
64,004 KB
testcase_08 AC 275 ms
60,796 KB
testcase_09 AC 251 ms
59,756 KB
testcase_10 AC 194 ms
59,388 KB
testcase_11 AC 354 ms
62,132 KB
testcase_12 AC 340 ms
63,872 KB
testcase_13 AC 336 ms
63,832 KB
testcase_14 AC 313 ms
63,520 KB
testcase_15 AC 271 ms
60,480 KB
testcase_16 AC 169 ms
59,444 KB
testcase_17 AC 250 ms
60,500 KB
testcase_18 AC 328 ms
64,320 KB
testcase_19 AC 309 ms
63,800 KB
testcase_20 AC 308 ms
64,296 KB
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 # 

public class Main {
  private static void solve() {
    int n = ni();
    int[] from = new int[n - 1];
    int[] to = new int[n - 1];

    for (int i = 0; i < n - 1; i++) {
      from[i] = ni() - 1;
      to[i] = ni() - 1;
    }
    int[][] g = packU(n, from, to);
    int[] ret = dfs(0, -1, g);
    System.out.println(Math.max(ret[0], ret[1]));
  }

  private static int[] dfs(int now, int pre, int[][] g) {
    int[] ret = {0, 1};
    for (int next : g[now]) {
      if (next == pre)
        continue;
      int[] v = dfs(next, now, g);
      ret[0] += Math.max(v[0], v[1]);
      ret[1] += Math.max(v[0], v[1] - 1);
    }
    return ret;
  }

  static int[][] packU(int n, int[] from, int[] to) {
    int[][] g = new int[n][];
    int[] p = new int[n];
    for (int f : from)
      p[f]++;
    for (int t : to)
      p[t]++;
    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];
      g[to[i]][--p[to[i]]] = from[i];
    }
    return g;
  }


  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));
  }
}
0