#include <bits/stdc++.h>
using namespace std;
#define ll long long
ll n,q,s,t,l,r,x,tmp,a[200001],d[200001];
int main(){
cin>>n>>q>>s>>t;
for (int i=0;i<=n;i++){
cin>>a[i];
if (i>0){
d[i]=a[i]-a[i-1];
if (d[i]>0) tmp-=d[i]*s;
else tmp-=d[i]*t;
}
}
while (q--){
cin>>l>>r>>x;
if (d[l]<0){
if (d[l]+x<0) tmp-=x*t;
else tmp+=d[l]*t-(d[l]+x)*s;
}
else{
if (d[l]+x>0) tmp-=x*s;
else tmp+=d[l]*s-(d[l]+x)*t;
}
if (r+1>n) goto a;
if (d[r+1]<0){
if (d[r+1]-x<0) tmp+=x*t;
else tmp+=d[r+1]*t-(d[r+1]-x)*s;
}
else{
if (d[r+1]-x>0) tmp+=x*s;
else tmp+=d[r+1]*s-(d[r+1]-x)*t;
}
d[r+1]-=x;
a:;
d[l]+=x;
cout<<tmp<<"\n";
}
}
