【Gym 100947I】What a Mess

#include <cstdio>
#include <cstring>
int n,t,b[1000001];
int main(){
    scanf("%d",&t);
    while(t--){
        memset(b,0,sizeof b);
        scanf("%d",&n);
        for(int i=1,a;i<=n;++i){
            scanf("%d",&a);
            ++b[a];
        }
        int ans=0;
        for(int i=2;i<=1000000;++i)if(b[i]){
            ans+=b[i]*(b[i]-1)/2;
            for(int j=i*2;j<=1000000;j+=i)
                ans+=b[i]*b[j];
        }
        printf("%d\n",ans);
    }
    return 0;
}