poj2402

简单题

View Code

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;

int n;

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d", &n), n)
    {
        long long x = 0;
        while (x * 2 < n)
            x = x * 10 + 9;
        if (n > x + x / 10)
        {
            n -= x;
            printf("%d", n);
            while (n > 0)
            {
                printf("%d", n % 10);
                n /= 10;
            }
        }
        else
        {
            n -= x / 10;
            printf("%d", n);
            n /= 10;
            while (n > 0)
            {
                printf("%d", n % 10);
                n /= 10;
            }
        }
        putchar('\n');
    }
    return 0;
}