bzoj5055 膜法师

 1 #include <bits/stdc++.h>
 2 #define il inline
 3 #define RG register
 4 #define ll long long
 5 #define rhl (19260817)
 6 #define N (300010)
 7 
 8 using namespace std;
 9 
10 int sum[20*N],ls[20*N],rs[20*N],rt[N],a[N],hsh[N],n,sz,tot,ans;
11 
12 il int gi(){
13   RG int x=0,q=1; RG char ch=getchar();
14   while ((ch<‘0‘ || ch>‘9‘) && ch!=‘-‘) ch=getchar();
15   if (ch==‘-‘) q=-1,ch=getchar();
16   while (ch>=‘0‘ && ch<=‘9‘) x=x*10+ch-48,ch=getchar();
17   return q*x;
18 }
19 
20 il void insert(RG int x,RG int &y,RG int l,RG int r,RG int p,RG int v){
21   sum[y=++sz]=sum[x]+v; if (sum[y]>=rhl) sum[y]-=rhl;
22   ls[y]=ls[x],rs[y]=rs[x]; if (l==r) return; RG int mid=(l+r)>>1;
23   p<=mid?insert(ls[x],ls[y],l,mid,p,v):insert(rs[x],rs[y],mid+1,r,p,v); return;
24 }
25 
26 il int query(RG int x,RG int y,RG int l,RG int r,RG int xl,RG int xr){
27   if (x==y) return 0;
28   if (xl<=l && r<=xr){
29     RG int res=sum[y]-sum[x];
30     return res<0 ? res+rhl : res;
31   }
32   RG int mid=(l+r)>>1;
33   if (xr<=mid) return query(ls[x],ls[y],l,mid,xl,xr);
34   if (xl>mid) return query(rs[x],rs[y],mid+1,r,xl,xr);
35   RG int res=query(ls[x],ls[y],l,mid,xl,mid)+query(rs[x],rs[y],mid+1,r,mid+1,xr);
36   return res>=rhl ? res-rhl : res;
37 }
38 
39 int main(){
40 #ifndef ONLINE_JUDGE
41   freopen("mogic.in","r",stdin);
42   freopen("mogic.out","w",stdout);
43 #endif
44   n=gi(); for (RG int i=1;i<=n;++i) a[i]=gi(),hsh[++tot]=a[i];
45   sort(hsh+1,hsh+tot+1),tot=unique(hsh+1,hsh+tot+1)-hsh-1;
46   for (RG int i=1;i<=n;++i){
47     a[i]=lower_bound(hsh+1,hsh+tot+1,a[i])-hsh;
48     insert(rt[i-1],rt[i],1,tot,a[i],hsh[a[i]]%rhl);
49   }
50   for (RG int i=2,l,r;i<n;++i){
51     l=a[i]>1 ? query(rt[0],rt[i],1,tot,1,a[i]-1) : 0;
52     r=a[i]<tot ? query(rt[i],rt[n],1,tot,a[i]+1,tot) : 0;
53     ans=(ans+1LL*l*r%rhl*hsh[a[i]])%rhl;
54   }
55   cout<<ans; return 0;
56 }