RUCP2016 Day3 D Complex Oracle - Complex Oracle -

問題

http://judge.u-aizu.ac.jp/onlinejudge/cdescription.jsp?cid=RitsCamp16Day3&pid=D

考察にめちゃくちゃ時間を奪われたので,もっと考察する時間を短縮させたい。

考察

• 

• 

は,

全体で番目の値より大きい値の数が分かれば,番目の値がこの数列の中で何番目に大きいのかが分かる。
それをN回繰り返せば元の数列が分かる。

解説:
http://www.slideshare.net/hcpc_hokudai/2016d-60984811

他の解説記事:

pekempeyさん
pekempey.hatenablog.com

kenkooooさん

kenkoooo.hatenablog.com

kenkoooo.hatenablog.com

kenkoooo.hatenablog.com

セグメント木を使う方法があったっぽいけど,全く思いつかなかった...。セグメント木を使う問題に慣れて無さ過ぎた...

ソースコード

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main implements Runnable{
	int N;
	int[] ans;
	long[] left,right;
	public long query(int l,int r){

		if(l == 1){
			if(left[r] == -1){
				out.println("? " + l + " " + r);
				out.flush();
				return left[r] = nextLong();
			}else{
				return left[r];
			}
		}else{

			if(right[l] == -1){
				out.println("? " + l + " " + r);
				out.flush();
				return right[l] = nextLong();
			}else{
				return right[l];
			}

		}

	}

	public void solve() {
		N = nextInt();

		ans = new int[N];
		left = new long[N+1];
		right = new long[N+1];
		Arrays.fill(left, -1);
		Arrays.fill(right, -1);

		for(int i = 1;i <= N;i++){

			int L = 0;
			int R = 0;

			if(i - 1 >= 1){
				L = (int)(query(1,i) - query(1,i-1));
			}

			if(i + 1 <= N){
				R = (int)(query(i,N) - query(i+1,N));
				R = (N - (i + 1) + 1) - R;
			}

			ans[i-1] = N - L - R;
		}
		out.print("!");
		for(int i = 0;i < N;i++){
			out.print(" " + ans[i]);
		}
		out.println();

	}

	public static void main(String[] args) {
		new Thread(null,new Main(),"",32 * 1024 * 1024).start();
	}

	/* Input */
	private static final InputStream in = System.in;
	private static final PrintWriter out = new PrintWriter(System.out);
	private final byte[] buffer = new byte[2048];
	private int p = 0;
	private int buflen = 0;

	private boolean hasNextByte() {
		if (p < buflen)
			return true;
		p = 0;
		try {
			buflen = in.read(buffer);
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (buflen <= 0)
			return false;
		return true;
	}

	public boolean hasNext() {
		while (hasNextByte() && !isPrint(buffer[p])) {
			p++;
		}
		return hasNextByte();
	}

	private boolean isPrint(int ch) {
		if (ch >= '!' && ch <= '~')
			return true;
		return false;
	}

	private int nextByte() {
		if (!hasNextByte())
			return -1;
		return buffer[p++];
	}

	public String next() {
		if (!hasNext())
			throw new NoSuchElementException();
		StringBuilder sb = new StringBuilder();
		int b = -1;
		while (isPrint((b = nextByte()))) {
			sb.appendCodePoint(b);
		}
		return sb.toString();
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

	public long nextLong() {
		return Long.parseLong(next());
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}

	@Override
	public void run() {
		out.flush();
		new Main().solve();
		out.close();

	}
}