結果

問題 No.826 連絡網
ユーザー OlandOland
提出日時 2019-05-03 22:06:31
言語 Java21
(openjdk 21)
結果
AC  
実行時間 104 ms / 2,000 ms
コード長 4,008 bytes
コンパイル時間 2,666 ms
コンパイル使用メモリ 81,596 KB
実行使用メモリ 39,364 KB
最終ジャッジ日時 2024-05-03 05:09:37
合計ジャッジ時間 5,646 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
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 53 ms
36,476 KB
testcase_01 AC 54 ms
37,112 KB
testcase_02 AC 52 ms
36,440 KB
testcase_03 AC 53 ms
37,112 KB
testcase_04 AC 53 ms
36,780 KB
testcase_05 AC 52 ms
36,960 KB
testcase_06 AC 53 ms
36,392 KB
testcase_07 AC 54 ms
36,852 KB
testcase_08 AC 52 ms
36,560 KB
testcase_09 AC 53 ms
36,532 KB
testcase_10 AC 52 ms
37,008 KB
testcase_11 AC 53 ms
37,048 KB
testcase_12 AC 87 ms
38,496 KB
testcase_13 AC 80 ms
38,044 KB
testcase_14 AC 82 ms
38,048 KB
testcase_15 AC 59 ms
36,872 KB
testcase_16 AC 76 ms
37,704 KB
testcase_17 AC 77 ms
38,024 KB
testcase_18 AC 75 ms
37,996 KB
testcase_19 AC 101 ms
39,092 KB
testcase_20 AC 88 ms
38,544 KB
testcase_21 AC 54 ms
36,780 KB
testcase_22 AC 76 ms
38,044 KB
testcase_23 AC 79 ms
38,240 KB
testcase_24 AC 71 ms
37,460 KB
testcase_25 AC 104 ms
39,000 KB
testcase_26 AC 70 ms
37,336 KB
testcase_27 AC 86 ms
38,188 KB
testcase_28 AC 82 ms
38,268 KB
testcase_29 AC 77 ms
37,564 KB
testcase_30 AC 101 ms
39,364 KB
testcase_31 AC 75 ms
37,952 KB
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ソースコード

diff # 

import java.io.*;
import java.util.*;
import java.util.Map.Entry;
import java.util.stream.Collectors;

@SuppressWarnings("unused")
public class Main {
	
	//final boolean isDebug = true;
	final boolean isDebug = false;
	String fileName = "input.txt";
	FastScanner sc;
	PrintWriter out;
	final int MOD = (int)1e9+7;
	final int INF = Integer.MAX_VALUE / 2;
	
	void solve() throws Exception{
		int N = sc.nextInt();
		int P = sc.nextInt();
		boolean[] isPrime = getPrime(N);
		if(P == 1 || (isPrime[P] && P * 2 > N)){
			System.out.println("1");
		}else{
			int count = 0;
			for(int i = 2; i <= N; i++){
				if(!isPrime[i] || (isPrime[i] && i * 2 <= N)) count++;
			}
			System.out.println(count);
		}
	}
	
	boolean[] getPrime(int n){
		boolean[] isPrime = new boolean[n+1];
		Arrays.fill(isPrime, true);
		
		if(n >= 0) isPrime[0] = false;
		if(n >= 1) isPrime[1] = false;
		
		for(int i = 2; i <= n; i++){
			if(isPrime[i]){
				for(int j = i + i; j <= n; j += i) isPrime[j] = false;
			}
		}
		
		return isPrime;
	}
	
	/* end solve */
	
	/* main */
	public static void main(String[] args) throws Exception {
		new Main().m();
	}
	
	void m() throws Exception {
		long S = System.currentTimeMillis();
		sc = (isDebug) ? new FastScanner(new FileInputStream(fileName)) : new FastScanner(System.in);
		out = new PrintWriter(System.out);
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		if(isDebug){
			System.out.println("---Debug---");
			System.out.printf("%8d ms", (G-S));
		}
	}
	/* end main */
}
/* end Main */

class FastScanner {
    private InputStream in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    public FastScanner(InputStream in) {
		this.in = in;
	}
    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();
    }
    public 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();
    }
    public String nextLine() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(b != 10) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public 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();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() {
    	return Double.parseDouble(next());
    }
}
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