学步园

    # include<cstdio>
    # include<cstring>

    # define MAX 2000

    int main(void)
    {
        int N;
        scanf("%d",&N);
        char S[MAX+8];
        int i;
        int count = 0;
        int a = 0;
        int b = N - 1;
          for ( i = 0;i < N;i++ )
          {
              scanf("\n%c",&S[i]);
          }
        while ( a <= b )
        {
          int left = 0;
            for ( i = 0; i+a <= b;i++ )
            {
                if ( S[i+a] < S[b-i] )
                    {
                        left = 1;
                        break;
                    }

            else if ( S[i+a] > S[b-i] )
            {
                   left = 0;
                    break;
            }
            }

            if ( left )
                putchar(S[a++]);
            else
                putchar(S[b--]);

                count++;
            if ( count == 80 )
               {
                   printf("\n");
                    count = 0;
               }

        }
        printf("\n");

        return 0;
    }