POJ 3994：Probability One

Probability One

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 1674		Accepted: 1151

Description

Number guessing is a popular game between elementary-school kids. Teachers encourage pupils to play the game as it enhances their arithmetic skills, logical thinking, and following-up simple procedures. We think that, most probably, you too will master in few
minutes. Here’s one example of how you too can play this game: Ask a friend to think of a number, let’s call it n0. Then:

Ask your friend to compute n1 = 3 * n0 and to tell you if n1 is even or odd.

If n1 is even, ask your friend to compute n2 = n1/2. If, otherwise, n1 was odd then let your friend compute n2 = (n1 + 1)/2.

Now ask your friend to calculate n3 = 3 * n2.

Ask your friend to tell tell you the result of n4 = n3/9. (n4 is the quotient of the division operation. In computer lingo, ’/’ is the integer-division operator.)

Now you can simply reveal the original number by calculating n0 = 2 * n4 if n1 was even, or n0 = 2 * n4 + 1 otherwise.

Here’s an example that you can follow: If n0 = 37, then n1 = 111 which is odd. Now we can calculate n2 = 56, n3 = 168, and n4 = 18, which is what your friend will tell you. Doing the calculation 2 * n4 +
1 = 37 reveals n0.
Input

Your program will be tested on one or more test cases. Each test case is made of a single positive number (0 < n0 < 1,000,000).

The last line of the input file has a single zero (which is not part of the test cases.)
Output

For each test case, print the following line:

k. B Q

Where k is the test case number (starting at one,) B is either ’even’ or ’odd’ (without the quotes) depending on your friend’s answer in step 1. Q is your friend’s answer to step 4.
Sample Input

37
38
0

Sample Output

1. odd 18
2. even 19

把整个过程换算完了就是把原数除以2。

代码：

#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
using namespace std;

int main()
{
int num,i=1;
while(cin>>num)
{
if(num==0)
break;
cout<<i<<". ";
i++;
if(num%2)
cout<<"odd ";
else
cout<<"even ";
cout<<num/2<<endl;
}
return 0;
}