結果

問題 No.1191 数え上げを愛したい（数列編）
ユーザー hiromi_ayasehiromi_ayase
提出日時 2020-08-22 17:56:17
言語 Java21
(openjdk 21)
結果
AC  
実行時間 122 ms / 2,000 ms
コード長 3,911 bytes
コンパイル時間 3,478 ms
コンパイル使用メモリ 83,568 KB
実行使用メモリ 55,412 KB
最終ジャッジ日時 2023-08-05 14:42:44
合計ジャッジ時間 7,085 ms
ジャッジサーバーID
（参考情報） 		judge12 / judge11
このコードへのチャレンジ（β）

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 74 ms
52,488 KB
testcase_01 AC 111 ms
53,468 KB
testcase_02 AC 83 ms
52,640 KB
testcase_03 AC 85 ms
54,584 KB
testcase_04 AC 105 ms
55,412 KB
testcase_05 AC 70 ms
52,508 KB
testcase_06 AC 122 ms
55,380 KB
testcase_07 AC 89 ms
54,516 KB
testcase_08 AC 87 ms
54,600 KB
testcase_09 AC 89 ms
52,960 KB
testcase_10 AC 69 ms
52,292 KB
testcase_11 AC 70 ms
52,448 KB
testcase_12 AC 110 ms
55,320 KB
testcase_13 AC 113 ms
55,156 KB
testcase_14 AC 122 ms
55,264 KB
testcase_15 AC 62 ms
50,792 KB
testcase_16 AC 62 ms
50,864 KB
testcase_17 AC 61 ms
50,700 KB
testcase_18 AC 61 ms
51,004 KB
testcase_19 AC 62 ms
50,804 KB
testcase_20 AC 67 ms
50,704 KB
testcase_21 AC 64 ms
51,172 KB
testcase_22 AC 71 ms
52,256 KB
testcase_23 AC 63 ms
50,712 KB
testcase_24 AC 60 ms
50,656 KB
testcase_25 AC 63 ms
50,888 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 # 

import java.util.Arrays;

public class Main {

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

    if (1 + (long) (n - 1) * a > m) {
      System.out.println(0);
      return;
    }

    m -= 1 + (n - 1) * a;
    b -= (n - 1) * a;

    int mod = 998244353;
    int[][] fif = enumFIF(m + n, mod);
    long ret = 0;
    for (int i = 0; i <= b; i++) {
      ret += CX(n + i - 2, i, mod, fif) * (m - i + 1) % mod;
      ret %= mod;
    }

    ret *= fif[0][n];
    ret %= mod;
    System.out.println(ret);
  }

  public static long CX(long n, long r, int p, int[][] fif) {
    if (n < 0 || r < 0 || r > n)
      return 0;
    int np = (int) (n % p), rp = (int) (r % p);
    if (np < rp)
      return 0;
    if (n == 0 && r == 0)
      return 1;
    int nrp = np - rp;
    if (nrp < 0)
      nrp += p;
    return (long) fif[0][np] * fif[1][rp] % p * fif[1][nrp] % p * CX(n / p, r / p, p, fif) % p;
  }

  public static int[][] enumFIF(int n, int mod) {
    int[] f = new int[n + 1];
    int[] invf = new int[n + 1];
    f[0] = 1;
    for (int i = 1; i <= n; i++) {
      f[i] = (int) ((long) f[i - 1] * i % mod);
    }
    long a = f[n];
    long b = mod;
    long p = 1, q = 0;
    while (b > 0) {
      long c = a / b;
      long d;
      d = a;
      a = b;
      b = d % b;
      d = p;
      p = q;
      q = d - c * q;
    }
    invf[n] = (int) (p < 0 ? p + mod : p);
    for (int i = n - 1; i >= 0; i--) {
      invf[i] = (int) ((long) invf[i + 1] * (i + 1) % mod);
    }
    return new int[][] { f, invf };
  }

  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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