蛇形矩阵

#include <stdio.h>
 int main() 
{  
     int i,j,n,k=0,sum,sn=1,sn1,m;
     while(scanf("%d",&n)!=EOF) 
    {    for(i=1;i<=n;i++) 
          {      
              {    
                printf("%d",sn);  
                sn1=sn;   
                for(j=k+2,m=1;m<=n-i;m++,j++)    
                    {   
                       sum=sn1+j;  
                       printf(" %d",sum); 
                       sn1=sum;   
                     }   
               printf("\n");     
               sn+=i;   
               k++;   
               }     
           }  
     }  
     return 0;
 }