学步园

　　水题，但是要细心

#include <stdio.h>
#include <stdlib.h>
#define N 10007
int a[N], b[N];
int cmp(const void * a, const void * b)
{
return *(int *)a - *(int *)b;
}
int main()
{
int n, i;
while(scanf("%d", &n) != EOF)
    {
for(i = 0; i < n; i++)
            scanf("%d", &a[i]);
        qsort(a, n, sizeof(a[0]), cmp);
int flag = 1,i = 0, j = n-1, k = 1;
while(i <= j)
        {
if(flag)
            {
                b[k++] = a[j--];
                flag = 0;
            }
else
            {
                b[k++] = a[i++];
                flag = 1;
            }
        }
for(i = 1; i < k-1; i++)
            printf("%d ", b[i]);
        printf("%d\n", b[k-1]);
    }
return 0;
}