#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=2e5+5;
int n,q,a[N],s,t,ans;
int f(int i){
if(i-1<0) return 0;
if(a[i]>0) return (-1)*a[i]*s;
else return (-1)*a[i]*t;
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> q >> s >> t;
for(int i=0;i<=n;i++) cin >> a[i];
for(int i=n;i>=1;i--) a[i]=a[i]-a[i-1];
//a[n+1]=0;
for(int i=1;i<=n;i++) ans+=f(i);
//cout << ans << "\n";
while(q--){
int l,r,d;
cin >> l >> r >> d;
//for(int i=0;i<=n+1;i++) cout << a[i] << " ";
//cout << "\n";
ans-=((r!=n?f(r+1):0)+f(l));
a[l]+=d;
a[r+1]-=d;
ans+=((r!=n?f(r+1):0)+f(l));
//for(int i=0;i<=n+1;i++) cout << a[i] << " ";
//cout << "\n";
cout << ans << "\n";
}
}
