TOANDFRO.cpp

// AC , ALGO : Adhoc, Implementation.

#include<cstdio>
#include<cstring>

using namespace std ;

int main( )
{
    char str[300] ;
    int c , r , n , i , j , flag , ctr ;
	
    scanf("%d",&c) ;
    
    while( c != 0 )
    {
 	scanf("%s",str) ;
		  
      	n = strlen( str ) ;
	r = n / c ;
		  
      	char a[r][c+1] ;
		
      	flag = -1 ;
	for( i = ctr = 0 ; i < r && ctr < n ; i++ )
	{
		flag *= -1 ;
		if( flag == 1 )
		{
                	for( j = 0 ; j < c ; j++ )
				a[i][j] = str[ctr++] ;
			a[i][j] = '\0' ;
		}
		else
		{
              		for( j = c - 1 ; j >= 0 ; j-- )
				a[i][j] = str[ctr++] ;
		}
	}
	for( i = 0 ; i < c ; i++ )
	{
		for( j = 0 ; j < r ; j++ )
			printf("%c",a[j][i]) ;
	}
		  
      	printf("\n") ;
      	scanf("%d",&c) ;
   } 
	
   return 0 ;
}