FZU 1891升降序列

题目：http://acm.hust.edu.cn/vjudge/contest/view.action?cid=110981#problem/C

代码：

#include<stdio.h>#include<string.h>#include<algorithm>using namespace std;int main(){    int t;    scanf("%d",&t);    while(t--)    {        int n;        scanf("%d",&n);        int a[50005];        for(int i=0;i<n;i++)        {            scanf("%d",&a[i]);        }        sort(a,a+n);        printf("%d",a[0]);        for(int i=1;i<n;i=i+2)        {            printf(" %d %d",a[i+1],a[i]);        }        printf("\n");    }}