UVA Building designing

题目总结来说求一段序列，必须正负交替，且绝对值递增

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <cmath>
#include <vector>
#include <algorithm>
using namespace std;
#define lowbit(x) (x&(-x))
#define max(x,y) (x>y?x:y)
#define min(x,y) (x<y?x:y)
#define mem(a) (memset(a,0,sizeof(a)))
typedef long long ll;
bool cmp(int a,int b)
{
    return abs(a)<abs(b);
}
int main()
{
    int t,n,a[];
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        for(int i=;i<n;i++)
        {
            scanf("%d",&a[i]);
        }
        sort(a,a+n,cmp);
        int ok=,ans=;
        if(a[]<) ok=;
        else ok=;
        for(int i=;i<n;i++)
        {
            if(ok== && a[i]<) ok=,ans++;
            else if(ok== && a[i]>) ok=,ans++;
        }
        printf("%d\n",ans);
    }
    return ;
}