bzoj4826 [Hnoi2017]影魔

 1 //It is made by wfj_2048~
 2 #include <algorithm>
 3 #include <iostream>
 4 #include <complex>
 5 #include <cstring>
 6 #include <cstdlib>
 7 #include <cstdio>
 8 #include <vector>
 9 #include <cmath>
10 #include <queue>
11 #include <stack>
12 #include <map>
13 #include <set>
14 #define inf (1<<30)
15 #define N (300010)
16 #define il inline
17 #define RG register
18 #define ll long long
19 #define File(s) freopen(s".in","r",stdin),freopen(s".out","w",stdout)
20 
21 using namespace std;
22 
23 struct data{ ll c,p,l,r; }q[4*N];
24 
25 ll sum[40*N],lazy[40*N],ls[40*N],rs[40*N],rt[N],sz;
26 ll lst[N],nxt[N],st[N],k[N],n,m,p1,p2,x,cnt,top;
27 
28 il ll gi(){
29     RG ll x=0,q=1; RG char ch=getchar();
30     while ((ch<‘0‘ || ch>‘9‘) && ch!=‘-‘) ch=getchar();
31     if (ch==‘-‘) q=-1,ch=getchar();
32     while (ch>=‘0‘ && ch<=‘9‘) x=x*10+ch-48,ch=getchar();
33     return q*x;
34 }
35 
36 il ll cmp(const data &a,const data &b){ return a.p<b.p; }
37 
38 il void update(RG ll x,RG ll &y,RG ll l,RG ll r,RG ll xl,RG ll xr,RG ll v){
39     lazy[y=++sz]=lazy[x],ls[y]=ls[x],rs[y]=rs[x];
40     if (xl<=l && r<=xr){ sum[y]=sum[x]+(r-l+1)*v,lazy[y]+=v; return; }
41     RG ll mid=(l+r)>>1;
42     if (xr<=mid) update(ls[x],ls[y],l,mid,xl,xr,v);
43     else if (xl>mid) update(rs[x],rs[y],mid+1,r,xl,xr,v);
44     else update(ls[x],ls[y],l,mid,xl,mid,v),update(rs[x],rs[y],mid+1,r,mid+1,xr,v);
45     sum[y]=sum[ls[y]]+sum[rs[y]]+(r-l+1)*lazy[y]; return;
46 }
47 
48 il ll query(RG ll x,RG ll y,RG ll l,RG ll r,RG ll xl,RG ll xr,RG ll la){
49     if (xl<=l && r<=xr) return sum[y]-sum[x]+(r-l+1)*la;
50     RG ll mid=(l+r)>>1; la+=lazy[y]-lazy[x];
51     if (xr<=mid) return query(ls[x],ls[y],l,mid,xl,xr,la);
52     else if (xl>mid) return query(rs[x],rs[y],mid+1,r,xl,xr,la);
53     else return query(ls[x],ls[y],l,mid,xl,mid,la)+query(rs[x],rs[y],mid+1,r,mid+1,xr,la);
54 }
55 
56 il void work(){
57     n=gi(),m=gi(),p1=gi(),p2=gi();
58     for (RG ll i=1;i<=n;++i){
59     k[i]=gi();
60     while (top && k[st[top]]<k[i]) nxt[st[top--]]=i;
61     lst[i]=st[top],st[++top]=i;
62     }
63     while (top) nxt[st[top--]]=n+1;
64     for (RG ll i=1;i<=n;++i){
65     if (lst[i] && nxt[i]<=n){
66         q[++cnt]=(data){1,lst[i],nxt[i],nxt[i]};
67         q[++cnt]=(data){1,nxt[i],lst[i],lst[i]};
68     }
69     if (lst[i] && nxt[i]-i>1)
70         q[++cnt]=(data){2,lst[i],i+1,nxt[i]-1};
71     if (nxt[i]<=n && i-lst[i]>1)
72         q[++cnt]=(data){2,nxt[i],lst[i]+1,i-1};
73     }
74     sort(q+1,q+cnt+1,cmp);
75     for (RG ll i=1;i<=cnt;++i){
76     while (x<q[i].p) rt[x+1]=rt[x],++x;
77     update(rt[x],rt[x],1,n,q[i].l,q[i].r,(q[i].c==1 ? p1 : 2*p2));
78     }
79     while (x<n) rt[x+1]=rt[x],++x;
80     for (RG ll i=1;i<=m;++i){
81     RG ll a=gi(),b=gi();
82     printf("%lld\n",query(rt[a-1],rt[b],1,n,a,b,0)/2+(b-a)*p1);
83     }
84     return;
85 }
86 
87 int main(){
88     File("sf");
89     work();
90     return 0;
91 }