結果

問題 No.843 Triple Primes
ユーザー uwiuwi
提出日時 2019-06-28 21:25:05
言語 Java21
(openjdk 21)
結果
AC  
実行時間 256 ms / 2,000 ms
コード長 4,684 bytes
コンパイル時間 4,534 ms
コンパイル使用メモリ 84,936 KB
実行使用メモリ 38,996 KB
最終ジャッジ日時 2024-09-19 13:47:09
合計ジャッジ時間 11,258 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge4
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 47 ms
36,828 KB
testcase_01 AC 256 ms
38,656 KB
testcase_02 AC 54 ms
36,488 KB
testcase_03 AC 51 ms
36,828 KB
testcase_04 AC 55 ms
36,956 KB
testcase_05 AC 56 ms
36,796 KB
testcase_06 AC 57 ms
37,144 KB
testcase_07 AC 211 ms
38,532 KB
testcase_08 AC 229 ms
38,684 KB
testcase_09 AC 255 ms
38,684 KB
testcase_10 AC 218 ms
38,760 KB
testcase_11 AC 237 ms
38,784 KB
testcase_12 AC 249 ms
38,808 KB
testcase_13 AC 246 ms
38,748 KB
testcase_14 AC 247 ms
38,764 KB
testcase_15 AC 221 ms
38,848 KB
testcase_16 AC 223 ms
38,708 KB
testcase_17 AC 50 ms
36,900 KB
testcase_18 AC 48 ms
36,964 KB
testcase_19 AC 47 ms
36,524 KB
testcase_20 AC 105 ms
38,552 KB
testcase_21 AC 104 ms
38,540 KB
testcase_22 AC 156 ms
38,556 KB
testcase_23 AC 162 ms
38,648 KB
testcase_24 AC 110 ms
38,728 KB
testcase_25 AC 102 ms
38,624 KB
testcase_26 AC 253 ms
38,996 KB
testcase_27 AC 66 ms
37,632 KB
testcase_28 AC 246 ms
38,616 KB
testcase_29 AC 113 ms
38,644 KB
testcase_30 AC 253 ms
38,944 KB
testcase_31 AC 85 ms
37,972 KB
testcase_32 AC 64 ms
37,432 KB
testcase_33 AC 145 ms
38,632 KB
testcase_34 AC 153 ms
38,652 KB
testcase_35 AC 252 ms
38,932 KB
testcase_36 AC 98 ms
38,424 KB
testcase_37 AC 203 ms
38,740 KB
testcase_38 AC 180 ms
38,832 KB
testcase_39 AC 250 ms
38,728 KB
testcase_40 AC 48 ms
36,944 KB
testcase_41 AC 49 ms
36,864 KB
testcase_42 AC 226 ms
38,736 KB
testcase_43 AC 249 ms
38,744 KB
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 # 

package contest190628;
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 C {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni();
		int[] primes = sieveEratosthenes(n);
		int ct = 0;
		for(int r : primes){
			if((long)r*r <= 2*n){
				for(int p : primes){
					if(p > r*r)break;
					if(Arrays.binarySearch(primes, r*r-p) >= 0){
						ct++;
					}
				}
			}
		}
		out.println(ct);
	}
	
	public static int[] sieveEratosthenes(int n) {
		if (n <= 32) {
			int[] primes = { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31 };
			for (int i = 0; i < primes.length; i++) {
				if (n < primes[i]) {
					return Arrays.copyOf(primes, i);
				}
			}
			return primes;
		}

		int u = n + 32;
		double lu = Math.log(u);
		int[] ret = new int[(int) (u / lu + u / lu / lu * 1.5)];
		ret[0] = 2;
		int pos = 1;

		int[] isnp = new int[(n + 1) / 32 / 2 + 1];
		int sup = (n + 1) / 32 / 2 + 1;

		int[] tprimes = { 3, 5, 7, 11, 13, 17, 19, 23, 29, 31 };
		for (int tp : tprimes) {
			ret[pos++] = tp;
			int[] ptn = new int[tp];
			for (int i = (tp - 3) / 2; i < tp << 5; i += tp)
				ptn[i >> 5] |= 1 << (i & 31);
			for (int j = 0; j < sup; j += tp) {
				for (int i = 0; i < tp && i + j < sup; i++) {
					isnp[j + i] |= ptn[i];
				}
			}
		}

		// 3,5,7
		// 2x+3=n
		int[] magic = { 0, 1, 23, 2, 29, 24, 19, 3, 30, 27, 25, 11, 20, 8, 4, 13, 31, 22, 28, 18, 26, 10, 7, 12, 21, 17,
				9, 6, 16, 5, 15, 14 };
		int h = n / 2;
		for (int i = 0; i < sup; i++) {
			for (int j = ~isnp[i]; j != 0; j &= j - 1) {
				int pp = i << 5 | magic[(j & -j) * 0x076be629 >>> 27];
				int p = 2 * pp + 3;
				if (p > n)
					break;
				ret[pos++] = p;
				if ((long) p * p > n)
					continue;
				for (int q = (p * p - 3) / 2; q <= h; q += p)
					isnp[q >> 5] |= 1 << q;
			}
		}

		return Arrays.copyOf(ret, pos);
	}

	
	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 C().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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