3105.txt

北大ACM题目例程 详细的解答过程 程序实现 算法分析

Source

Problem Id:3105  User Id:fzk 
Memory:4556K  Time:4993MS
Language:Java  Result:Accepted

Source 

import java.util.*;
import java.io.*;
import java.lang.reflect.Array;

public class Main {
		
	static public void main( String [] string ) throws Exception{
		Scanner cin = new Scanner( System.in );
		int m = cin.nextInt();
		int n, i, p1, p0, s;
		double v;
		while( (m--) > 0 ) {
			s = n = cin.nextInt();
			v = 0;
			for( i=1; i<n; i<<=1 ) {
				if( (s&1) == 1 ) {
					p0 = (s/2+1)*i;
					p1 = n-p0;
				}
				else {
					p1 = s/2*i;
					p0 = n-p1;
				}
				v += i*(2.0*p1/n*p0/n);
				s >>= 1;
			}
			System.out.printf( "%.2f\n", new Object[]{ Double.valueOf(v) } );
		}
		return;
	}
}