#include <bits/stdc++.h> //Andrei Alexandru a.k.a Sho10
#define ll long long
#define double long double
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define all(a) (a).begin(), (a).end()
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pi pair
#define rc(s) return cout<<s,0
#define endl '\n'
#define mod (10*10*10*10*10*10*10*10*10+7)
#define PI 3.14159265359
#define MAXN 100005
#define INF 1000000005
#define LINF 1000000000000000005ll
#define CODE_START ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
ll n,a[200005],d[200005],q,s,t;
int32_t main(){
CODE_START;
cin>>n>>q>>s>>t;
for(ll i=0;i<=n;i++)
{
cin>>a[i];
if(i){
d[i]=a[i]-a[i-1];
}
}
ll ans=0;
for(ll i=1;i<=n;i++)
{
if(d[i]>0){
ans-=s*d[i];
}else {
ans-=t*d[i];
}
}
while(q--){
ll l,r,x;
cin>>l>>r>>x;
if(d[l]>0){
ans+=d[l]*s;
}else {
ans+=d[l]*t;
}
d[l]+=x;
if(d[l]>0){
ans-=d[l]*s;
}else {
ans-=d[l]*t;
}
if(r<n){
if(d[r+1]>0){
ans+=d[r+1]*s;
}else {
ans+=d[r+1]*t;
}
d[r+1]-=x;
if(d[r+1]>0){
ans-=d[r+1]*s;
}else ans-=d[r+1]*t;
}
cout<<ans<<endl;
}
}
