#include<bits/stdc++.h>
using namespace std;
long long n,q,s,t,l,r,x,diff[200005];
long long a[200005],sum_pos,sum_neg;
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin>>n>>q>>s>>t;
for(int i=0;i<=n;i++){
cin>>a[i];
if(i>0){
diff[i]=a[i]-a[i-1];
}
}
for(int i=1;i<=n;i++){
if(diff[i]>0){
sum_pos+=diff[i];
}else{
sum_neg+=diff[i];
}
}
for(int vl=1;vl<=q;vl++){
cin>>l>>r>>x;
long long tmp1=diff[l]+x;
long long tmp2=diff[r+1]-x;
if(diff[l]>0){
sum_pos-=diff[l];
}else{
sum_neg-=diff[l];
}
if(tmp1>0){
sum_pos+=tmp1;
}else{
sum_neg+=tmp1;
}
if(r+1<=n){
if(diff[r+1]>0){
sum_pos-=diff[r+1];
}else{
sum_neg-=diff[r+1];
}
if(tmp2>0){
sum_pos+=tmp2;
}else{
sum_neg+=tmp2;
}
}
diff[l]=tmp1;
diff[r+1]=tmp2;
cout<<abs(sum_neg)*t-abs(sum_pos)*s<<endl;
}
}
