結果

問題 No.794 チーム戦 (2)
ユーザー threepipes_s
提出日時 2019-02-22 23:08:38
言語 Java
(openjdk 23)
結果
WA  
実行時間 -
コード長 4,223 bytes
コンパイル時間 2,266 ms
コンパイル使用メモリ 80,256 KB
実行使用メモリ 47,808 KB
最終ジャッジ日時 2024-11-25 21:46:49
合計ジャッジ時間 12,003 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 12 WA * 20
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.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.Closeable;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.util.*;

public class Main implements Runnable {
    static ContestScanner in;
    static Writer out;
    public static void main(String[] args) {
        new Thread(null, new Main(), "", 16 * 1024 * 1024).start();
    }

    public void run() {
        Main main = new Main();
        try {
            in = new ContestScanner();
            out = new Writer();
            main.solve();
            out.close();
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    void solve() throws IOException {
        long mod = 1000000007;
        int n = in.nextInt();
        int k = in.nextInt();
        long[] a = new long[n];
        for (int i = 0; i < a.length; i++) {
            a[i] = in.nextLong();
        }
        Arrays.sort(a);
        long ans = 1;
        int i = n - 1;
        int j = 0;
        for (j = 0; i >= 0; i--, j++) {
            if (a[i] * 2 <= k) break;
            int id = Arrays.binarySearch(a, k - a[i]);
//            if (id < 0) System.out.println((id) + ":" + (-1 - id));
//            else System.out.println(id);
            if (id == -1) {
                System.out.println(0);
                return;
            }
            if (id < 0) id = -id - 2;
            id += 1;
            if (id - j < 0) {
                System.out.println(0);
                return;
            }
            ans = (ans * (id - j)) % mod;
        }

        for (int l = 0; l < (n - j * 2) / 2 - 1; l++, i-=2) {
            ans = ans * i % mod * (i + 1) % mod * modinv(2, mod) % mod * modinv(l + 2, mod) % mod;
        }
        System.out.println(ans);
    }

    long modinv(long n, long mod){
        return modpow(n, mod-2, mod);
    }

    long modpow(long n, long a, long mod){
        long res = 1;
        while(a > 0){
            if((a&1)==1) res = (res * n) % mod;
            n = n * n % mod;
            a >>= 1;
        }
        return res;
    }
}


@SuppressWarnings("serial")
class MultiSet<T> extends HashMap<T, Integer>{
    @Override public Integer get(Object key){return containsKey(key)?super.get(key):0;}
    public void add(T key,int v){put(key,get(key)+v);}
    public void add(T key){put(key,get(key)+1);}
    public void sub(T key){final int v=get(key);if(v==1)remove(key);else put(key,v-1);}
    public MultiSet<T> merge(MultiSet<T> set)
    {MultiSet<T>s,l;if(this.size()<set.size()){s=this;l=set;}else{s=set;l=this;}
        for(Entry<T,Integer>e:s.entrySet())l.add(e.getKey(),e.getValue());return l;}
}

class Writer extends PrintWriter{
    public Writer(String filename)throws IOException
    {super(new BufferedWriter(new FileWriter(filename)));}
    public Writer()throws IOException{super(System.out);}
}
class ContestScanner implements Closeable{
    private BufferedReader in;private int c=-2;
    public ContestScanner()throws IOException
    {in=new BufferedReader(new InputStreamReader(System.in));}
    public ContestScanner(String filename)throws IOException
    {in=new BufferedReader(new InputStreamReader(new FileInputStream(filename)));}
    public String nextToken()throws IOException {
        StringBuilder sb=new StringBuilder();
        while((c=in.read())!=-1&&Character.isWhitespace(c));
        while(c!=-1&&!Character.isWhitespace(c)){sb.append((char)c);c=in.read();}
        return sb.toString();
    }
    public String readLine()throws IOException{
        StringBuilder sb=new StringBuilder();if(c==-2)c=in.read();
        while(c!=-1&&c!='\n'&&c!='\r'){sb.append((char)c);c=in.read();}
        return sb.toString();
    }
    public long nextLong()throws IOException,NumberFormatException
    {return Long.parseLong(nextToken());}
    public int nextInt()throws NumberFormatException,IOException
    {return(int)nextLong();}
    public double nextDouble()throws NumberFormatException,IOException
    {return Double.parseDouble(nextToken());}
    public void close() throws IOException {in.close();}
}
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