cf B. Levko and Permutation

http://codeforces.com/contest/361/problem/B
 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 int n,k;
 7 
 8 int main()
 9 {
10     while(scanf("%d%d",&n,&k)!=EOF)
11     {
12         if(n==k)
13         {
14             printf("-1
");
15             continue;
16         }
17         int m=n-k;
18         if(m==1)
19         {
20             for(int i=1; i<=n; i++)
21             {
22                 if(i==1) printf("%d",1);
23                 else printf(" %d",i);
24             }
25         }
26         else if(m==2)
27         {
28             for(int i=1; i<=n ;i++)
29             {
30                 if(i==1) printf("%d",n);
31                 else if(i==n) printf(" %d
",1);
32                 else printf(" %d",i);
33             }
34         }
35         else
36         {
37             int m1=m-2;
38             printf("%d",n-m1);
39             int cnt=1;
40             int j;
41             for(j=2; j<=n-1-m1; j++)
42             {
43                 printf(" %d",j);
44             }
45             for(int i=j; i<=n; i++)
46             {
47                 if(i==n) printf(" 1
");
48                 else printf(" %d",i+1);
49             }
50         }
51     }
52     return 0;
53 }
View Code