#include <bits/stdc++.h>
using namespace std;
int const MAX=2e5+5;
int n,q,s,t;
long long v[MAX];
void read(){
cin>>n>>q>>s>>t;
int i;
for(i=0;i<=n;++i)
cin>>v[i];
for(i=n;i;--i)
v[i]-=v[i-1];
}
long long delta(long long val){
if(val>0)
return -1LL*s*val;
else
return -1LL*t*val;
}
void process_queries(){
long long temp=0;
int i;
for(i=1;i<=n;++i)
temp+=delta(v[i]);
while(q--){
int l,r,d;
cin>>l>>r>>d;
temp-=delta(v[l]);
v[l]+=d;
temp+=delta(v[l]);
if(r<n){
temp-=delta(v[r+1]);
v[r+1]-=d;
temp+=delta(v[r+1]);
}
cout<<temp<<'\n';
}
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
read();
process_queries();
return 0;
}
