#include<bits/stdc++.h>
#define ll long long
using namespace std;
int n,q,s,t,i,j,l,r,v;
ll a[200010],S[800010],lazy[800010],h1,h2,h3,h4,tmp;
void build(int node,int l,int r){
if(l==r){
S[node]=a[l];
return;
}
int mid=(r+l)/2;
build(node*2,l,mid);
build(node*2+1,mid+1,r);
}
void check(int node,int l,int r){
if(lazy[node]==0) return;
if(l==r){
S[node]+=lazy[node];
}
else{
lazy[node*2]+=lazy[node];
lazy[node*2+1]+=lazy[node];
}
lazy[node]=0;
}
ll query(int node,int l,int r,int M){
check(node,l,r);
if(l==r) return S[node];
int mid=(r+l)/2;
if(M<=mid) return query(node*2,l,mid,M);
return query(node*2+1,mid+1,r,M);
}
void update(int node,int l,int r,int L,int R,int val){
check(node,l,r);
if(l>R || r<L) return;
if(l>=L && r<=R){
lazy[node]+=val;
return;
}
int mid=(r+l)/2;
update(node*2,l,mid,L,R,val);
update(node*2+1,mid+1,r,L,R,val);
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n >> q >> s >> t;
for(i=0;i<=n;i++) cin >> a[i];
for(i=0;i<n;i++){
if(a[i]<a[i+1]) tmp-=(a[i+1]-a[i])*s;
else tmp+=(a[i]-a[i+1])*t;
}
build(1,1,n);
for(j=1;j<=q;j++){
cin >> l >> r >> v;
h1=(l==1 ? 0 : query(1,1,n,l-1));
h2=query(1,1,n,l);
h3=query(1,1,n,r);
h4=(r==n ? h3 : query(1,1,n,r+1));
if(h1<h2) tmp+=(h2-h1)*s;
else tmp-=(h1-h2)*t;
if(h3<h4) tmp+=(h4-h3)*s;
else tmp-=(h3-h4)*t;
update(1,1,n,l,(r<n ? r : r+1),v);
h2=query(1,1,n,l);
h3=query(1,1,n,r);
if(r==n) h4=h3;
if(h1<h2) tmp-=(h2-h1)*s;
else tmp+=(h1-h2)*t;
if(h3<h4) tmp-=(h4-h3)*s;
else tmp+=(h3-h4)*t;
cout << tmp << "\n";
}
}
