POJ 4011

ACM ICPC 2011–2012, NEERC, Northern Subregional Contest
St Petersburg, October 29, 2011
Problem A. Automated Telephone Exchange

Input file: ate.in
Output file: ate.out
Time limit: 3 seconds
Memory limit: 256 megabytes
In St Petersburg phone numbers are formatted as “XXX–XX–XX”, where the first three digits represent index of the Automated Telephone Exchange (ATE). Each ATE has exactly 10 000 unique phone numbers.
Peter has just bought a new flat and now he wants to install a telephone line. He thinks that a phone number is lucky if the arithmetic expression represented by that phone number is equal to zero. For example, the phone number 102–40–62 is lucky (102 – 40 – 62 = 0), and the number 157–10–47 is not lucky (157 – 10 – 47 = 100 ≠ 0).
Peter knows the index of the ATE that serves his house. To get an idea of his chances to get a lucky number he wants to know how many lucky numbers his ATE has.
Input
The input file contains a single integer number n — the index of Peter’s ATE (100 ≦ n ≦ 999).
Output
Output a single integer number — the number of lucky phone numbers Peter’s ATE has.
Examples

ate.in	ate.out
196	3
239	0

水题：

#include 
#include 
using namespace std;
int main()
{
    int n;
    while(scanf("%d",&n) != EOF)
    {
      int ans = 0;
      if(n >= 199)
      printf("0\n");
      else
      {
        if(n % 2 == 0)
        {
          ans = 1+ 2*(99 - n/2);
        }
        else
        {
          ans = 2*(100 - (n+1)/2);
        }
        printf("%d\n", ans);
      }
    }
    return 0;
}