結果
| 問題 | No.2351 Butterfly in Summer |
| ユーザー |
 Asahi
|
| 提出日時 | 2023-06-16 22:58:57 |
| 言語 | Java (openjdk 23) |
| 結果 |
AC
|
| 実行時間 | 84 ms / 2,000 ms |
| コード長 | 6,913 bytes |
| コンパイル時間 | 2,563 ms |
| コンパイル使用メモリ | 84,336 KB |
| 実行使用メモリ | 57,460 KB |
| 最終ジャッジ日時 | 2024-06-24 15:58:54 |
| 合計ジャッジ時間 | 5,438 ms |
|
ジャッジサーバーID （参考情報） |
judge4 / judge2 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 21 |
ソースコード
import java.util.*;import java.io.*;class Main{void solve(PrintWriter out, In in) {int n = in.nextInt() , k = in.nextInt();long MOD = 998244353;Combination cm = new Combination(1000000,MOD);// kC2 * 2 * N!/(N-1)!long kC2 = cm.nck(k,2) % MOD;long combi = cm.facts[n] * cm.inv(cm.facts[n-1]) % MOD;long high = kC2 * 2 * combi % MOD;long low = cm.modpow(k,n) % MOD;out.print(high * cm.inv(low) % MOD);}class Combination {int n;long mod;long[] facts;Combination(int n, long mod) {this.n = n;this.mod = mod;facts = new long[n];facts[0] = 1;for (int i = 1; i < n; i++) {facts[i] = facts[i - 1] * i % mod;}}long modpow(long a, long b) {if (b == 0) return 1;else if (b == 1) return a;long x = modpow(a, b / 2);return b % 2 == 0 ? x * x % mod : x * (x * a % mod) % mod;}long inv(long n) {return modpow(n, mod - 2);}long nck(int n, int k) {return facts[n] * (inv(facts[n - k]) * inv(facts[k]) % mod) % mod;}}public static void main(String[] args) {PrintWriter out = new PrintWriter(System.out);In in = new In();new Main().solve(out,in);out.flush();}}class Pair implements Comparable<Pair>{private int first ;private int second;Pair(int first,int second) {this.first = first;this.second = second;}int first() {return this.first ;}int second() {return this.second;}@Overridepublic boolean equals(Object o) {if (!(o instanceof Pair)) {return false;}Pair that = (Pair)o;return first == that.first && second == that.second;}@Overridepublic int hashCode() {return Objects.hash(first, second);}@Overridepublic int compareTo(Pair o) {return first == o.first ? Integer.compare(second, o.second) : Integer.compare(first, o.first);}@Overridepublic String toString(){return first()+" "+second();}}class PairII {private int first;private int second;private int third;PairII(int first, int second, int third) {this.first = first;this.second = second;this.third = third;}int first() {return this.first;}int second() {return this.second;}int third() {return this.third;}@Overridepublic boolean equals(Object obj) {if (this == obj) {return true;}if (obj == null || getClass() != obj.getClass()) {return false;}PairII other = (PairII) obj;return this.first == other.first && this.second == other.second && this.third == other.third;}@Overridepublic int hashCode() {int result = 17;result = 31 * result + first;result = 31 * result + second;result = 31 * result + third;return result;}@Overridepublic String toString() {return this.first+" "+this.second+" "+this.third;}}class In{private final InputStream in = System.in;private final byte[] buffer = new byte[1024];private int ptr = 0;private int buflen = 0;private boolean hasNextByte() {if (ptr < buflen) {return true;}else{ptr = 0;try {buflen = in.read(buffer);} catch (IOException e) {e.printStackTrace();}if (buflen <= 0) {return false;}}return true;}private int readByte() {if (hasNextByte()) return buffer[ptr++]; else return -1;}private static boolean isPrintableChar(int c) {return 33 <= c && c <= 126;}public boolean hasNext() {while(hasNextByte() && !isPrintableChar(buffer[ptr])) {ptr++;}return hasNextByte();}String next() {if (!hasNext()) throw new NoSuchElementException();StringBuilder sb = new StringBuilder();int b = readByte();while(isPrintableChar(b)) {sb.appendCodePoint(b);b = readByte();}return sb.toString();}long nextLong() {if (!hasNext()) throw new NoSuchElementException();long n = 0;boolean minus = false;int b = readByte();if (b == '-') {minus = true;b = readByte();}if (b < '0' || '9' < b) {throw new NumberFormatException();}while(true){if ('0' <= b && b <= '9') {n *= 10;n += b - '0';}else if(b == -1 || !isPrintableChar(b)){return minus ? -n : n;}else{throw new NumberFormatException();}b = readByte();}}int nextInt() {long nl = nextLong();if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();return (int) nl;}double nextDouble() {return Double.parseDouble(next());}int [] IntArray(int n) {final int [] Array = new int [n];for(int i = 0 ; i < n ; i ++ ) {Array[i] = nextInt();}return Array;}int [][] IntArray(int n , int m) {final int [][] Array = new int [n][m];for(int i = 0 ; i < n ; i ++ ) {Array[i] = IntArray(m);}return Array;}long [] LongArray(int n) {final long [] Array = new long [n];for(int i = 0 ; i < n ; i ++ ) {Array[i] = nextLong();}return Array;}long [][] LongArray(int n , int m) {final long [][] Array = new long [n][m];for(int i = 0 ; i < n ; i ++ ) {Array[i] = LongArray(m);}return Array;}String [] StringArray(int n) {final String [] Array = new String [n];for(int i = 0 ; i < n ; i ++ ) {Array[i] = next();}return Array;}char [] CharArray(int n) {final char [] Array = new char[n];for(int i = 0 ; i < n ; i ++ ) {Array[i] = next().charAt(0);}return Array;}char [][] CharArray(int n , int m) {final char [][] Array = new char [n][m];for(int i = 0 ; i < n ; i ++ ) {Array[i] = next().toCharArray();}return Array;}}