BZOJ 4240 有趣的家庭菜园

#include<cstring>
#include<cstdio>
#include<algorithm>
#define N 300005
#define lowbit(_i) (_i&-_i)
using namespace std;
namespace runzhe2000
{
typedef long long ll;
int n, a
, rk
, mx, q
, tail; ll ans;
struct BIT
{
int t
; BIT(){memset(t,0,sizeof t);}
int ask(int x){int r = 0; for(; x; x -= lowbit(x)) r += t[x]; return r;}
void mod(int x){for(; x <= n; x += lowbit(x)) t[x]++;}
}T;
bool cmp(int u, int v){return a[u] > a[v];}
void main()
{
scanf("%d",&n);
for(int i = 1; i <= n; i++) scanf("%d",&a[i]), rk[i] = i;
sort(rk+1, rk+1+n, cmp);
for(int i = 1, tot = 0; i <= n; i++)
{
if(a[rk[i]] != a[rk[i-1]]) {tot += tail; for(; tail; tail--) T.mod(q[tail]);}
int x = rk[i], lef = T.ask(x-1), rig = tot-lef;
ans += min(lef, rig); q[++tail] = x;
}
printf("%lld\n",ans);
}
}
int main()
{
runzhe2000::main();
}