#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,qu,s,t;
int brp(int a){
if(a>0)return -a*s;
return -a*t;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>qu>>s>>t;
int a[n+1];
for(int q=0;q<=n;q++)cin>>a[q];
int diff[n+1];
int ans=0;
for(int q=1;q<=n;q++){
diff[q]=a[q]-a[q-1];
ans+=brp(diff[q]);
}
while(qu--){
int l,r,x;
cin>>l>>r>>x;
// l ke l-1
ans-=brp(diff[l]);
diff[l]+=x;
ans+=brp(diff[l]);
if(r!=n){
// r ke r+1
ans-=brp(diff[r+1]);
diff[r+1]-=x;
ans+=brp(diff[r+1]);
}
cout<<ans<<endl;
}
}
