結果

問題 No.979 Longest Divisor Sequence
ユーザー lavox
提出日時 2021-12-02 20:24:06
言語 Java
(openjdk 23)
結果
AC  
実行時間 763 ms / 2,000 ms
コード長 3,572 bytes
コンパイル時間 2,587 ms
コンパイル使用メモリ 80,056 KB
実行使用メモリ 101,508 KB
最終ジャッジ日時 2024-07-05 02:04:48
合計ジャッジ時間 10,951 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge5
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ファイルパターン 結果
other AC * 16
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.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {
	public static void main(String[] args) {
		Main o = new Main();
		o.solve();
	}

	public void solve() {
		FastScanner sc = new FastScanner(System.in);
		int N = sc.nextInt();
		int[] A = new int[N];
		for (int i = 0; i < N; i++) {
			A[i] = sc.nextInt();
		}

		int AMAX = 300001;
		ArrayList<Integer>[] factor = new ArrayList[AMAX];
		for (int i = 0; i < AMAX; i++) {
			factor[i] = new ArrayList<>();
		}

		boolean[] p = new boolean[AMAX];
		Arrays.fill(p, true);
		for (int i = 2; i < AMAX; i++) {
			if ( !p[i] ) continue;

			int cur = i;
			factor[i].add(i);
			while ( (cur += i) < AMAX ) {
				p[cur] = false;
				factor[cur].add(i);
			}
		}

		int[] max = new int[AMAX];
		//max[1] = 1;
		for (int i = 0; i < N; i++) {
			int[] pow = new int[factor[A[i]].size()];
			int cnt = 1;
			int a = A[i];
			for (int j = 0; j < factor[A[i]].size(); j++) {
				int pr = factor[A[i]].get(j);
				while ( a % pr == 0 ) {
					pow[j]++;
					a /= pr;
				}
				cnt *= (pow[j] + 1);
			}
			int[] d = new int[cnt];
			divisor(factor[A[i]], pow, 0, 1, 0, d);

			if ( A[i] == 1 ) {
				max[1] = 1;
			} else {
				int m = max[A[i]];
				for ( int f : d ) {
					if ( f == A[i] ) continue;
	
					m = Math.max(m, max[f] + 1);
				}
				max[A[i]] = m;
			}
		}

		int ans = 0;
		for (int i = 0; i < AMAX; i++) {
			ans = Math.max(max[i], ans);
		}

		System.out.println(ans);
	}

	int divisor(ArrayList<Integer> f, int[] pow, int cur, int num, int i, int[] div) {
		if ( cur >= pow.length ) {
			div[i++] = num;
			return i;
		}
		for (int j = 0; j <= pow[cur]; j++) {
			i = divisor(f, pow, cur + 1, num, i, div);
			num *= f.get(cur);
		}
		return i;
	}

	class FastScanner {
		private final InputStream in;
		private final byte[] buf = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;
		FastScanner( InputStream source ) { this.in = source; }
		private boolean hasNextByte() {
			if ( ptr < buflen ) return true;
			else {
				ptr = 0;
				try { buflen = in.read(buf); } catch (IOException e) { e.printStackTrace(); }
				if ( buflen <= 0 ) return false;
			}
			return true;
		} 
		private int readByte() { if ( hasNextByte() ) return buf[ptr++]; else return -1; } 
		private boolean isPrintableChar( int c ) { return 33 <= c && c <= 126; }
		private boolean isNumeric( int c ) { return '0' <= c && c <= '9'; }
		private void skipToNextPrintableChar() { while ( hasNextByte() && !isPrintableChar(buf[ptr]) ) ptr++; }
		public boolean hasNext() { skipToNextPrintableChar(); return hasNextByte(); }
		public String next() {
			if ( !hasNext() ) throw new NoSuchElementException();
			StringBuilder ret = new StringBuilder();
			int b = readByte();
			while ( isPrintableChar(b) ) { ret.appendCodePoint(b); b = readByte(); }
			return ret.toString();
		}
		public long nextLong() {
			if ( !hasNext() ) throw new NoSuchElementException();
			long ret = 0;
			int b = readByte();
			boolean negative = false;
			if ( b == '-' ) { negative = true; if ( hasNextByte() ) b = readByte(); }
			if ( !isNumeric(b) ) throw new NumberFormatException();
			while ( true ) {
				if ( isNumeric(b) ) ret = ret * 10 + b - '0';
				else if ( b == -1 || !isPrintableChar(b) ) return negative ? -ret : ret;
				else throw new NumberFormatException();
				b = readByte();
			}
		}
		public int nextInt() { return (int)nextLong(); }
		public double nextDouble() { return Double.parseDouble(next()); }
	}
}
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