結果

問題 No.308 素数は通れません
ユーザー threepipes_s
提出日時 2015-12-05 10:10:33
言語 Java
(openjdk 23)
結果
AC  
実行時間 93 ms / 1,000 ms
コード長 4,183 bytes
コンパイル時間 2,879 ms
コンパイル使用メモリ 81,324 KB
実行使用メモリ 39,660 KB
最終ジャッジ日時 2024-11-27 18:40:30
合計ジャッジ時間 9,760 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
other AC * 107
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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

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayDeque;
import java.util.BitSet;
import java.util.HashMap;
import java.util.Queue;
 
public class Main {
    public static void main(String[] args) throws NumberFormatException,
    IOException {Solve solve = new Solve();solve.solve();}
}
class Solve{
    void solve() throws NumberFormatException, IOException{
        ContestScanner in = new ContestScanner();
        Writer out = new Writer();
//      if(exp()) return;
        BigInteger bi = new BigInteger(in.readLine());
        if(bi.compareTo(BigInteger.valueOf(40L))>=0){
            if(bi.mod(BigInteger.valueOf(8)).equals(BigInteger.valueOf(1))
                    && bi.add(BigInteger.valueOf(-8)).isProbablePrime(100)) System.out.println(14);
            else System.out.println(8);
            return;
        }
        BitSet p = prime(50);
        int n = bi.intValue();
        for(int w=3; w<n; w++){
            final int h = (n+w-1)/w;
            boolean[][] map = new boolean[h][w];
            for(int i=0; i<n; i++){
                final int y = i/w;
                final int x = i%w;
                map[y][x] = p.get(i+1);
            }
            if(n%w!=0) for(int i=n%w; i<w; i++){
                map[h-1][i] = true;
            }
//          for(int i=0; i<h; i++){
//              for(int j=0; j<w; j++){
//                  System.out.print(map[i][j]?'X':'.');
//              }
//              System.out.println();
//          }
//          System.out.println();
            if(check(map, n-1)){
                System.out.println(w);
                return;
            }
        }
        System.out.println(n-1);
    }
    
    boolean exp(){
        int n = 100;
        BitSet p = prime(n);
        for(int i=1; i<=n; i++){
            if(p.get(i)) System.out.print('X');
            else System.out.print('.');
            if(i%8==0) System.out.println();
        }
        return true;
    }
    
    final int[] dx = {0, 1, 0, -1};
    final int[] dy = {1, 0, -1, 0};
    boolean check(boolean[][] map, int goal){
        final int h = map.length;
        final int w = map[0].length;
        Queue<Integer> qu = new ArrayDeque<>();
        qu.add(0);
        BitSet used = new BitSet(h*w);
        while(!qu.isEmpty()){
            int p = qu.poll();
            if(used.get(p)) continue;
            used.set(p);
            if(goal==p) return true;
            final int y = p/w;
            final int x = p%w;
            for(int i=0; i<4; i++){
                final int ny = dy[i]+y;
                final int nx = dx[i]+x;
                if(ny<0||ny>=h||nx<0||nx>=w||map[ny][nx])
                    continue;
                qu.add(ny*w+nx);
            }
        }
        return false;
    }
    
    public static BitSet prime(int max){
        // こちらを使うように
        BitSet prime = new BitSet(max+1);
        prime.set(2, max+1);
        for(int i=2; i!=-1 && i*i<=max; i=prime.nextSetBit(i+1))
            for(int j=i*2; j<=max; j+=i) prime.clear(j);
        return prime;
    }
}
 
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);}
}
class Timer{
    long time;
    public void set(){time = System.currentTimeMillis();}
    public long stop(){return System.currentTimeMillis()-time;}
}
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 {
    private BufferedReader reader;
    private String[] line;
    private int idx;
    public ContestScanner() throws FileNotFoundException 
    {reader = new BufferedReader(new InputStreamReader(System.in));}
    public ContestScanner(String filename) throws FileNotFoundException
    {reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));}
    public String nextToken() throws IOException {
        if (line == null || line.length <= idx) {
            line = reader.readLine().trim().split(" ");
            idx = 0;
        }
        return line[idx++];
    }
    public String readLine() throws IOException{return reader.readLine();}
    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());}
}
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