#include <bits/stdc++.h>
#define f first
#define s second
#define ll long long
using namespace std;
const int maxn=2e5+5;
const int INF=1e9;
int n,q,s,t;
int a[maxn],diff[maxn];
ll calc(int val)
{
if(val<0) return -val*t;
else return -val*s;
}
int main()
{
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];
ll ans=0;
for(int i=1;i<=n;i++){
diff[i]=a[i]-a[i-1];
ans+=calc(diff[i]);
}
while(q--){
int l,r,x;
cin>>l>>r>>x;
ans-=calc(diff[l]);
diff[l]+=x;
ans+=calc(diff[l]);
if(r<n){
ans-=calc(diff[r+1]);
diff[r+1]-=x;
ans+=calc(diff[r+1]);
}
cout<<ans<<'\n';
}
}
