hdu 2492树状数组

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#include<stdio.h>
#include<string.h>
#define max 100010 
int b[max],c[max];
__int64 x[max],y[max];
int a[max];
int lowbit(int x)
{
return x&(-x);
}
void update(int arr[],int x)
{
while(x<=max)
    {
        arr[x]++;
        x+=lowbit(x);
    }
}
__int64 sum(int arr[],int x)
{
    __int64 ans=0;
while(x>0)
    {
        ans+=arr[x];
        x-=lowbit(x);
    }
return ans;
}
int main()
{
int t,i,n;
    __int64  ans;
    scanf("%d",&t);
while(t--)
    {
        ans=0;
        memset(b,0,sizeof(b));
        memset(c,0,sizeof(c));
        scanf("%d",&n);
for(i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
        }
for(i=1;i<=n;i++)
        {
            x[i]=sum(b,a[i]-1);
            update(b,a[i]);
        }
for(i=n;i>=1;i--)
        {
            y[i]=sum(c,a[i]-1);
            update(c,a[i]);
        }
for(i=1;i<=n;i++)
        {
            ans+=(__int64(x[i]*(n-i-y[i]))+__int64((i-1-x[i])*y[i]));
        }
        printf("%I64d\n",ans);
    }
return 0;
}