求助，裸树状数组过不了，吸氧能过

#include <bits/stdc++.h>
#define lowbit(x) x&-x
#define N 500001
#define int long long
using namespace std;
int n,ans=0,tot=1,sp;
int p[N],tr[N];
struct fuck {
	int w,bh;
} sb[N];
map<int,int> lsh;
bool cmp(fuck a,fuck b) {
	return a.w<b.w;
}
void change(int xx,int y) {
	int x=xx;
	while(x<=n) {
		tr[x]+=y;
		x+=lowbit(x);
	}
}
int ask(int xx) {
	int sum=0,x=xx;
	while(x) {
		sum+=tr[x];
		x-=lowbit(x);
	}
	return sum;
}
signed main() {
	scanf("%d",&n);
	sp=n;
	for(int i=1; i<=n; i++) {
		scanf("%d",&sb[i].w);
		sb[i].bh=i;
		lsh[i]=0;
	}
	sort(sb+1,sb+1+n,cmp);
	for(int i=1; i<=n; i++) {
		if(lsh[sb[i].w]==lsh.end) lsh[sb[i].w]=tot,tot++;
		p[sb[i].bh]=lsh[sb[i].w];
	}//离散化 
	for(int i=1; i<=n; i++) change(p[i],1);
	for(int i=n; i>=1; i--) {
		ans+=(sp-ask(p[i]));
		change(p[i],-1);
		sp--;
	}
	printf("%d",ans);
	return 0;
}