#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;
const long long MAXN = 200100;
long long arr[MAXN];
long long n,q,s1,s2;
long long diff[MAXN];
long long get(long long x){
if(x<0){
return -s2*x;
}else{
return -s1*x;
}
}
int main() {
cin>>n>>q>>s1>>s2;
for(long long i=0;i<=n;i++){
cin>>arr[i];
}
long long ans = 0;
for(long long i=0;i<n;i++){
diff[i] = arr[i+1]-arr[i];
ans+=get(diff[i]);
}
// cout<<ans<<endl;
while(q--){
long long l,r,x;
cin>>l>>r>>x;
ans-=get(diff[l-1]);
diff[l-1]+=x;
ans+=get(diff[l-1]);
if(r!=n){
ans-=get(diff[r]);
diff[r]-=x;
ans+=get(diff[r]);
}
cout<<ans<<endl;
}
}
