結果

問題 No.1191 数え上げを愛したい（数列編）
ユーザー uwiuwi
提出日時 2020-08-22 15:24:58
言語 Java21
(openjdk 21)
結果
AC  
実行時間 113 ms / 2,000 ms
コード長 4,446 bytes
コンパイル時間 5,483 ms
コンパイル使用メモリ 91,044 KB
実行使用メモリ 55,776 KB
最終ジャッジ日時 2024-10-15 09:37:43
合計ジャッジ時間 7,427 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge5
このコードへのチャレンジ
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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 93 ms
55,284 KB
testcase_01 AC 107 ms
55,660 KB
testcase_02 AC 96 ms
55,448 KB
testcase_03 AC 96 ms
55,240 KB
testcase_04 AC 108 ms
55,776 KB
testcase_05 AC 91 ms
55,232 KB
testcase_06 AC 113 ms
55,500 KB
testcase_07 AC 95 ms
55,232 KB
testcase_08 AC 97 ms
55,344 KB
testcase_09 AC 96 ms
55,416 KB
testcase_10 AC 90 ms
55,632 KB
testcase_11 AC 90 ms
55,284 KB
testcase_12 AC 105 ms
55,608 KB
testcase_13 AC 108 ms
55,604 KB
testcase_14 AC 109 ms
55,544 KB
testcase_15 AC 53 ms
50,192 KB
testcase_16 AC 55 ms
50,344 KB
testcase_17 AC 53 ms
50,132 KB
testcase_18 AC 55 ms
50,188 KB
testcase_19 AC 55 ms
50,104 KB
testcase_20 AC 53 ms
50,164 KB
testcase_21 AC 54 ms
49,932 KB
testcase_22 AC 89 ms
55,356 KB
testcase_23 AC 91 ms
55,200 KB
testcase_24 AC 54 ms
50,088 KB
testcase_25 AC 89 ms
55,124 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 # 

package gioku2020day1;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class J2 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni(), m = ni(), A = ni(), B = ni();
		if((long)A*(n-1) > B){
			out.println(0);
			return;
		}
		
		// 1 0 0 0
		// 1 1 1 1
		// 1 2 3 4
		// 1 3 6 10
		
		// (x^A*(-1)/(x-1))^(n-1)
		int mod = 998244353;
		int[][] fif = enumFIF(600000, mod);
		long ans = 0;
		for(int i = A*(n-1), j = 0, k = 1;i <= B;i++,j++, k = mod-k){
			ans += C(i-A*(n-1) + n-2, n-2, mod, fif) * (m-i);
			ans %= mod;
		}
		out.println(ans*fif[0][n] % mod);
	}
	
	public static long pow(long a, long n, long mod) {
		//		a %= mod;
		long ret = 1;
		int x = 63 - Long.numberOfLeadingZeros(n);
		for (; x >= 0; x--) {
			ret = ret * ret % mod;
			if (n << 63 - x < 0)
				ret = ret * a % mod;
		}
		return ret;
	}

	
	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 long C(int n, int r, int mod, int[][] fif) {
		if (n < 0 || r < 0 || r > n)
			return 0;
		return (long) fif[0][n] * fif[1][r] % mod * fif[1][n - r] % mod;
	}

	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
//			@Override
//			public void run() {
//				long s = System.currentTimeMillis();
//				solve();
//				out.flush();
//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//			}
//		};
//		t.start();
//		t.join();
	}
	
	public static void main(String[] args) throws Exception { new J2().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		return a;
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for(int i = 0;i < n;i++)map[i] = na(m);
		return map;
	}
	
	private int ni() { return (int)nl(); }
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}
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