#include<bits/stdc++.h>
using namespace std;
long long n,q,s,t;
long long a[200200];
long long base=0;
struct NODE
{
long long add=0;
NODE *l=NULL,*r=NULL;
} *root;
NODE* build(int l,int r)
{
NODE *ptr = new NODE;
if(l==r)
{
ptr->add=a[l];
return ptr;
}
int mid=(l+r)/2;
ptr->l=build(l,mid);
ptr->r=build(mid+1,r);
return ptr;
}
long long val;
int ll,rr;
void update(NODE *ptr,int l,int r)
{
if(ll<=l&&r<=rr)
{
ptr->add+=val;
return ;
}
else if(r<ll||rr<l)
return ;
int mid=(l+r)/2;
update(ptr->l,l,mid);
update(ptr->r,mid+1,r);
return ;
}
int po;
long long query(NODE *ptr,int l,int r)
{
if(l==r)
return ptr->add;
int mid=(l+r)/2;
if(po<=mid)
return ptr->add+query(ptr->l,l,mid);
else
return ptr->add+query(ptr->r,mid+1,r);
}
main()
{
scanf("%lld %lld %lld %lld",&n,&q,&s,&t);
for(int i=0;i<n+1;i++)
{
scanf("%lld",&a[i]);
if(i)
{
if(a[i-1]<a[i])
base-=s*(a[i]-a[i-1]);
else
base+=t*(a[i-1]-a[i]);
}
}
root=build(0,n);
//printf("%lld\n",base);
for(int i=0;i<q;i++)
{
long long l,r,x;
scanf("%lld %lld %lld",&l,&r,&x);
long long cha=0;
po=l-1;
long long prell=query(root,0,n);
po=l;
long long prel=query(root,0,n);
//printf("-%lld %lld-\n",prell,prel);
if(prell<prel)
cha-=s*(prel-prell);
else
cha+=t*(prell-prel);
if(r!=n)
{
po=r+1;
long long prerr=query(root,0,n);
po=r;
long long prer=query(root,0,n);
//printf("-%lld %lld-\n",prer,prerr);
if(prer<prerr)
cha-=s*(prerr-prer);
else
cha+=t*(prer-prerr);
}
cha*=-1;
ll=l;
rr=r;
val=x;
update(root,0,n);
po=l-1;
long long postll=query(root,0,n);
po=l;
long long postl=query(root,0,n);
//printf("-%lld %lld-\n",postll,postl);
if(postll<postl)
cha-=s*(postl-postll);
else
cha+=t*(postll-postl);
if(r!=n)
{
po=r+1;
long long postrr=query(root,0,n);
po=r;
long long postr=query(root,0,n);
//printf("-%lld %lld-\n",postr,postrr);
if(postr<postrr)
cha-=s*(postrr-postr);
else
cha+=t*(postr-postrr);
}
base+=cha;
printf("%lld\n",base);
}
}
