#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pll pair<int, int>
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define endl '\n'
signed main(){
int n,q,s,t;
cin>>n>>q>>s>>t;
vector<int> v(n+5,0), d(n+5, 0);
int ans=0;
for(int i=0;i<=n;i++){
cin>>v[i];
if(i > 0){
d[i]=v[i]-v[i-1];
if(d[i] >= 0){ans-=s*d[i];}
else {ans+=-t*d[i];}
}
}
//~ cout<<"ans is "<<ans<<endl;
while(q--){
int l,r,x,i;cin>>l>>r>>x;
i=l;
if(d[i] >= 0){ans+=s*d[i];}
else {ans-=-t*d[i];}
d[i]+=x;
if(d[i] >= 0){ans-=s*d[i];}
else {ans+=-t*d[i];}
//~ printf("after balancing l, ans is %lld\n", ans);
if(r < n){
i=r+1;
if(d[i] >= 0){ans+=s*d[i];}
else {ans-=-t*d[i];}
d[i]-=x;
if(d[i] >= 0){ans-=s*d[i];}
else {ans+=-t*d[i];}
}
//~ int sm=0;
//~ cout<<endl<<"sm is \n";
//~ for(int i=0;i<=n;i++){
//~ sm+=d[i];
//~ cout<<sm<<" ";
//~ }
//~ cout<<endl<<"d is \n";
//~ for(int i=0;i<=n;i++){
//~ cout<<d[i]<<" ";
//~ }
//~ cout<<endl;
cout<<ans<<"\n";
}
}
