#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define pll pair<ll,ll>
#define fi first
#define se second
const ll inf=2e18;
const int maxN=3e5+5;
int n,q;
ll a[maxN+1],b[maxN+1],s,t,ans=0;
void add(int i)
{
if(b[i]>0)
{
ans+=(b[i]*s);
}
else ans+=(b[i]*t);
}
void del(int i)
{
if(b[i]>0)
{
ans-=(b[i]*s);
}
else ans-=(b[i]*t);
}
int main()
{
//freopen("","r",stdin);
//freopen("","w",stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>q>>s>>t;
for(int i=0;i<=n;i++)
{
cin>>a[i];
}
for(int i=1;i<=n;i++)
{
b[i]=a[i]-a[i-1];
if(b[i]>0)
{
ans-=(b[i]*s);
}
else ans-=(b[i]*t);
}
while(q--)
{
int l,r;
ll x;
cin>>l>>r>>x;
add(l);
if(r+1<=n)
{
add(r+1);
}
b[l]+=x;
if(r+1<=n)
{
b[r+1]-=x;
}
del(l);
if(r+1<=n)
{
del(r+1);
}
cout<<ans<<'\n';
}
}
