結果

問題 No.626 Randomized 01 Knapsack
ユーザー uwiuwi
提出日時 2018-01-19 22:24:28
言語 Java21
(openjdk 21)
結果
AC  
実行時間 89 ms / 2,000 ms
コード長 4,358 bytes
コンパイル時間 4,405 ms
コンパイル使用メモリ 81,152 KB
実行使用メモリ 39,240 KB
最終ジャッジ日時 2024-06-26 03:35:46
合計ジャッジ時間 6,553 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge3
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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 50 ms
36,612 KB
testcase_01 AC 53 ms
36,852 KB
testcase_02 AC 51 ms
36,904 KB
testcase_03 AC 51 ms
36,744 KB
testcase_04 AC 50 ms
36,620 KB
testcase_05 AC 51 ms
37,112 KB
testcase_06 AC 52 ms
37,140 KB
testcase_07 AC 55 ms
36,644 KB
testcase_08 AC 55 ms
37,004 KB
testcase_09 AC 62 ms
37,392 KB
testcase_10 AC 61 ms
37,460 KB
testcase_11 AC 87 ms
38,964 KB
testcase_12 AC 89 ms
38,924 KB
testcase_13 AC 86 ms
39,112 KB
testcase_14 AC 87 ms
39,240 KB
testcase_15 AC 87 ms
38,924 KB
testcase_16 AC 89 ms
39,112 KB
testcase_17 AC 88 ms
39,152 KB
testcase_18 AC 86 ms
39,056 KB
testcase_19 AC 85 ms
39,068 KB
testcase_20 AC 88 ms
39,092 KB
testcase_21 AC 88 ms
39,192 KB
testcase_22 AC 87 ms
38,880 KB
testcase_23 AC 87 ms
38,976 KB
testcase_24 AC 76 ms
38,712 KB
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ソースコード

diff # 

package yukicoder;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Comparator;
import java.util.InputMismatchException;
import java.util.Random;

public class N626 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni();
		long W = nl();
		long[][] vw = new long[n][];
		for(int i = 0;i < n;i++){
			vw[i] = new long[]{nl(), nl()};
		}
		Arrays.sort(vw, new Comparator<long[]>() {
			public int compare(long[] a, long[] b) {
				return -Double.compare((double)a[0]/a[1], (double)b[0]/b[1]);
			}
		});
		maxv = 0;
		dfs(0, 0L, W, vw);
		out.println(maxv);
	}
	
	long maxv;
	long s;
	
	void dfs(int pos, long v, long w, long[][] vw)
	{
		if(v > maxv){
			maxv = v;
		}
		if(pos == vw.length)return;
		
		// 途中まで貪欲にとる
		long simv = v;
		long simw = w;
		int i = pos;
		for(;i < vw.length && simw-vw[i][1] >= 0;i++){
			simv += vw[i][0];
			simw -= vw[i][1];
		}
		// それ以降は適当に推理
		if(simv + (i < vw.length ? (double)vw[i][0] * simw / vw[i][1] : 0) + 10 <= maxv)return;
		
		if(w-vw[pos][1] >= 0){
			dfs(pos+1, v+vw[pos][0], w-vw[pos][1], vw);
		}
		
		dfs(pos+1, v, w, vw);
	}
	
	long big(Random gen)
	{
		return Math.abs(gen.nextLong() % 1000000000000L) + 1;
	}
	
	void run() throws Exception
	{
//		int n = 5000, m = 99999;
//		Random gen = new Random(1);
//		StringBuilder sb = new StringBuilder();
//		sb.append(n + " ");
//		sb.append(big(gen) + " ");
//		for (int i = 0; i < n; i++) {
//			sb.append(big(gen) + " ");
//			sb.append(big(gen) + "\n");
//		}
//		INPUT = sb.toString();

		
		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 N626().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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