#include
#define maxn 100010
struct data
{
int num,cnt;
}A[maxn],temp[maxn];
int n;
//long long ans;
long long ANS[100];
void merge(int L1,int R1,int L2,int R2)
{
int k=0,i=L1,j=L2;
while(i<=R1 && j<=R2)
{
if(A[i].num<=A[j].num)//如果A[i].num
{
A[i].cnt+=j-L2;
temp[k++]=A[i++];
}
else if(A[i].num>A[j].num)//A[i,R1]都大于A[j]
{
A[j].cnt+=R1-i+1;
temp[k++]=A[j++];
}
}
//剩下上数组，那么剩下的元素都要移动下数组的元素个数
while(i<=R1)
{
A[i].cnt+=R2-L2+1;
temp[k++]=A[i++];
}
while(j<=R2) temp[k++]=A[j++]; //剩下下数组，就不需要移动
for(i=0;i
}
void mergeSort(int L,int R)
{
if(L
{
int mid = (L+R)/2;
mergeSort(L,mid);
mergeSort(mid+1,R);
merge(L,mid,mid+1,R);
}
}
int main(void)
{
//FILE *in = fopen("input10.txt","r");
//fscanf(in,"%d",&n);
//for(int i=0;i
scanf("%d",&n);
for(int i=0;i
mergeSort(0,n-1);
for(int i=0;i
{
long long s = A[i].cnt;
//ans+=s*(s+1)/2;
ANS[1]+=s*(s+1)/2;
int length=1;
while(ANS[length]/10!=0)
{
ANS[length+1]+=ANS[length]/10;
ANS[length]%=10;
length++;
}
if(ANS[0]
}
//printf("%lld",ans);
for(int i=ANS[0];i>=1;i--) printf("%d",ANS[i]);
//printf("\n");
return 0;
}
)
)
