#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define fi first
#define se second
#define pb push_back
#define TC int t; cin>>t; while(t--)
#define all(x) (x).begin(),(x).end()
//*AC BERSAMA ALLAH FORTIS FORTUNA ADIUVAT
ll n,q,s,t;
vector<ll> v, dif;
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin>>n>>q>>s>>t;
v.resize(n+5);
dif.resize(n+5);
ll sneg=0, spos=0, val=0; // stored in positive
for(int i=0;i<=n;i++){
cin>>v[i];
if(i>0){
dif[i] = v[i]-v[i-1];
if(dif[i]<=0) sneg += (dif[i]*-1);
else spos += dif[i];
}
}
// val = sneg * t - spos * s;
// cout<<"::"<<spos<<"--"<<sneg<<'\n';
// cout<<"=="<<val<<'\n';
for(int i=1;i<=q;i++){
ll l,r,x;
cin>>l>>r>>x;
if(dif[l]<=0) sneg += dif[l];
else spos -= dif[l];
if(r==n);
else if(dif[r+1]<=0) sneg += dif[r+1];
else spos -= dif[r+1];
// cout<<"::"<<spos<<"--"<<sneg<<'\n';
dif[l] += x;
dif[r+1] -= x;
if(dif[l]<=0) sneg -= dif[l];
else spos += dif[l];
if(r==n);
else if(dif[r+1]<=0) sneg -= dif[r+1];
else spos += dif[r+1];
// cout<<"::"<<spos<<"--"<<sneg<<'\n';
val = sneg * t - spos * s;
cout<<val<<'\n';
// cout<<val<<'\n';
}
return 0;
}
