hdu1390Binary Numbers

Problem Description
Given a positive integer n, find the positions of all 1’s in its binary representation. The position of the least significant bit is 0.

Example

The positions of 1’s in the binary representation of 13 are 0, 2, 3.

Task

Write a program which for each data set:

reads a positive integer n,

computes the positions of 1’s in the binary representation of n,

writes the result.

Input
The first line of the input contains exactly one positive integer d equal to the number of data sets, 1 <= d <= 10. The data sets follow.

Each data set consists of exactly one line containing exactly one integer n, 1 <= n <= 10^6.

Output
The output should consists of exactly d lines, one line for each data set.

Line i, 1 <= i <= d, should contain increasing sequence of integers separated by single spaces - the positions of 1’s in the binary representation of the i-th input number.

Sample Input

1
13

Sample Output

0 2 3

分析：题目意思就是把数化为2进制，输出位数为1的位置。看了下数据，果断打表了！

#include<iostream>
#include<cstring>
#include<algorithm>
#include<string>
using namespace std;
int a[]={1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536 ,131072,262144,524288};
int b[50],t,n;
int main()
{
    cin>>t;
    while(t--)
    {
        cin>>n;
        int rel=0;
        for(int i=19;i>=0;i--)
        {
            if(n>=a[i])
            {
                n-=a[i];
                b[rel++]=i;
            }
        }
        for(int i=rel-1;i>=0;i--)
        {
            cout<<b[i];
            i==0?cout<<endl:cout<<" "; 
        }
    }
    return 0;
 }