結果

問題 No.573 a^2[i] = a[i]
ユーザー uwi
提出日時 2017-10-06 22:47:10
言語 Java
(openjdk 23)
結果
AC  
実行時間 116 ms / 2,000 ms
コード長 4,642 bytes
コンパイル時間 4,135 ms
コンパイル使用メモリ 88,032 KB
実行使用メモリ 40,588 KB
最終ジャッジ日時 2024-11-17 01:49:30
合計ジャッジ時間 7,971 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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ファイルパターン 結果
other AC * 47
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ソースコード

diff #
プレゼンテーションモードにする

package contest171006;
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 F {
    InputStream is;
    PrintWriter out;
    String INPUT = "";
    
    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;
    }
    
    void solve()
    {
        int mod = 1000000007;
        int n = ni();
        int[][] fif = enumFIF(300000, mod);
        long ans = 0;
        for(int k = 0;k <= n;k++){
            ans += C(n, k, mod, fif) * pow(n-k, k, mod);
            ans %= mod;
        }
        out.println(ans);
//      int n = 5;
//      int[] a = new int[n];
//      int ct = 0;
//      outer:
//      do{
//          for(int i = 0;i < n;i++){
//              if(a[i] != a[a[i]])continue outer;
//          }
//          ct++;
//      }while(inc(a, n));
//      tr(ct);
    }
    
    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;
    }
    
    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 boolean inc(int[] a, int base) {
        int n = a.length;
        int i;
        for (i = n - 1; i >= 0 && a[i] == base - 1; i--)
            ;
        if (i == -1)
            return false;
        a[i]++;
        Arrays.fill(a, i + 1, n, 0);
        return true;
    }
    
    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 F().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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