#include<bits/stdc++.h>
using namespace std;
long long n,q,s,t,a[200050],ans,b[200050];
void d(int x,int k){
	if(b[x]>0) ans-=b[x]*t;
	if(b[x]<0) ans-=b[x]*s;
	b[x]+=k;
	if(b[x]>0) ans+=b[x]*t;
	if(b[x]<0) ans+=b[x]*s;
}
int main(){
	freopen("foehn.in","r",stdin);
	freopen("foehn.out","w",stdout);
	cin>>n>>q>>s>>t;
	for(long long i=0;i<=n;i++){
		cin>>a[i];
		if(i){
			b[i]=a[i-1]-a[i];
		}
		if(b[i]>0){
			ans+=b[i]*t;
		}else if(b[i]<0){
			ans+=b[i]*s;
		}
	}
	for(long long i=1;i<=q;i++){
		long long l,r,x;
		cin>>l>>r>>x;
		d(l,-x);
		if(r+1<=n){
			d(r+1,x);
		}
		
		cout<<ans<<endl;
	}
	return 0;
}