結果

問題 No.75 回数の期待値の問題
ユーザー uwiuwi
提出日時 2014-11-24 04:41:00
言語 Java21
(openjdk 21)
結果
AC  
実行時間 127 ms / 5,000 ms
コード長 4,069 bytes
コンパイル時間 2,182 ms
コンパイル使用メモリ 83,404 KB
実行使用メモリ 41,676 KB
最終ジャッジ日時 2024-06-10 22:02:19
合計ジャッジ時間 5,284 ms
ジャッジサーバーID
（参考情報） 		judge3 / 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 106 ms
40,216 KB
testcase_01 AC 117 ms
41,420 KB
testcase_02 AC 115 ms
41,324 KB
testcase_03 AC 114 ms
41,512 KB
testcase_04 AC 117 ms
41,344 KB
testcase_05 AC 126 ms
41,260 KB
testcase_06 AC 113 ms
40,420 KB
testcase_07 AC 112 ms
40,300 KB
testcase_08 AC 116 ms
41,540 KB
testcase_09 AC 113 ms
41,432 KB
testcase_10 AC 114 ms
41,456 KB
testcase_11 AC 116 ms
41,260 KB
testcase_12 AC 115 ms
41,324 KB
testcase_13 AC 121 ms
41,568 KB
testcase_14 AC 116 ms
41,120 KB
testcase_15 AC 116 ms
41,460 KB
testcase_16 AC 122 ms
41,676 KB
testcase_17 AC 104 ms
40,576 KB
testcase_18 AC 113 ms
40,868 KB
testcase_19 AC 127 ms
41,676 KB
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ソースコード

diff # 

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 Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int K = ni();
		double[][] p = new double[K+2][K+7];
		p[0][0] = 1;
		for(int i = 0;i < K+1;i++){
			for(int j = 0;j < K;j++){
				if(p[i][j] > 0){
					for(int f = 1;f <= 6;f++){
						p[i+1][j+f] += p[i][j] / 6;
					}
				}
			}
		}
		
		double goalp = 0;
		double goale = 0;
		for(int i = 0;i < K+2;i++){
			goalp += p[i][K];
			goale += i*p[i][K];
		}
		double overe = 0;
		for(int i = 0;i < K+2;i++){
			for(int j = K+1;j < K+7;j++){
				overe += i*p[i][j];
			}
		}
		// ge + oe+(1-gp)oe+(1-gp)^2*oe+...
		// 1+(1-gp)+(1-gp)^2+..
		// (1-gp)gp+2(1-gp)^2*gp+..
		// (1-gp)/gp^2
		double E = (overe+goale)/goalp;
		out.printf("%.12f\n", E);
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static 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 static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static 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 static 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 static 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 static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, 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 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) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}
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