#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll v1[200001];
int main(){
ll n,q,s1,t; cin>>n>>q>>s1>>t;
ll a[n+1];
for(ll i=0;i<=n;i++){
cin>>a[i];
}
ll sum1=0,sum2=0;
for(ll i=0;i<n;i++){
v1[i+1]=a[i]-a[i+1];
if(a[i]-a[i+1]>0) sum2+=(a[i]-a[i+1]);
else sum1+=a[i]-a[i+1];
}
while(q--){
ll l,r,x; cin>>l>>r>>x; r++;
if(v1[l]>=0){
sum2-=v1[l];
v1[l]-=x;
if(v1[l]>=0) sum2+=v1[l];
else sum1+=v1[l];
}
else{
sum1-=v1[l];
v1[l]-=x;
if(v1[l]>=0) sum2+=v1[l];
else sum1+=v1[l];
}
if(r-1==n){ cout<<sum1*s1+sum2*t<<endl; continue;}
if(v1[r]>=0){
sum2-=v1[r];
v1[r]+=x;
if(v1[r]>=0) sum2+=v1[r];
else sum1+=v1[r];
}
else{
sum1-=v1[r];
v1[r]+=x;
if(v1[r]>=0) sum2+=v1[r];
else sum1+=v1[r];
}
cout<<sum1*s1+sum2*t<<endl;
}
}
