#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
#define FF first
#define SS second
#define all(a) a.begin(), a.end()
#define mod (ll)(1000000007)
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
ll n, q, s, t;
cin>>n>>q>>s>>t;
vector<int>A(n+1);
for(int i=0;i<=n;i++){
cin>>A[i];
}
ll cur=0;
vector<ll>diff(n);
for(int i=0;i<n;i++){
diff[i]=A[i+1]-A[i];
}
for(int i=0;i<n;i++){
if(diff[i]>0)
cur+=diff[i]*(-s);
else
cur+=diff[i]*(-t);
}
while(q--){
int l, r, x;
cin>>l>>r>>x;
cur-=diff[l-1]*-(diff[l-1]>0?s:t)+(r!=n?diff[r]*-(diff[r]>0?s:t):0);
diff[l-1]+=x;
if(r!=n)
diff[r]-=x;
cur+=diff[l-1]*-(diff[l-1]>0?s:t)+(r!=n?diff[r]*-(diff[r]>0?s:t):0);
cout<<cur<<endl;
}
}
