#include <bits/stdc++.h>
using namespace std;
#define forn(i,n) for(int i=0;i<int(n);i++)
#define forsn(i,s,n) for(int i=int(s);i<int(n);i++)
#define dforn(i,n) for(int i=int(n)-1;i>=0;i--)
#define dforsn(i,s,n) for(int i=int(n)-1;i>=int(s);i--)
#define fst first
#define snd second
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef pair<int,int> ii;
const int N=2e5+9;
ll ft[N];
void upd(int p, ll v){
for(++p;p<N;p+=p&-p) ft[p]+=v;
}
void upd(int l, int r, ll v){
upd(l,v);
upd(r+1,-v);
}
ll query(int p){
ll s=0;
for(++p;p>0;p-=p&-p) s+=ft[p];
return s;
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,q; ll s,t;
cin>>n>>q>>s>>t;
forn(i,n+1){
int a; cin>>a;
upd(i,i,a);
}
ll ret=0LL;
auto delta=[&](int i){
if(i==n) return 0LL;
ll a=query(i);
ll b=query(i+1);
if(a<b) return s*(a-b);
return t*(a-b);
};
forn(i,n) ret+=delta(i);
forn(i,q){
int l,r,x;
cin>>l>>r>>x;
ret-=delta(l-1);
ret-=delta(r);
upd(l,r,x);
ret+=delta(l-1);
ret+=delta(r);
cout<<ret<<'\n';
}
return 0;
}
