cf B. Permutation

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;

 int a[];
 int main()
 {
     int n,k;
     scanf("%d%d",&n,&k);
     for(int i=; i<=*n; i++)
     {
         a[i]=i;
     }
     for(int i=; i<=k; i++)
     {
         swap(a[*i-],a[*i]);
     }
     for(int i=; i<=*n; i++)
     {
         if(i==) printf("%d",a[i]);
         else printf(" %d",a[i]);
     }
     printf("\n");
     return ;
 }

http://codeforces.com/contest/359/problem/B

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;

 int n,k;

 int main()
 {
     while(scanf("%d%d",&n,&k)!=EOF)
     {
        printf("%d",k+);
        for(int i=; i<=*n; i++)
        {
            if(i!=k+) printf(" %d",i);
        }
        printf("\n");
     }
     return ;
 }