//Coded by Chirath Nirodha
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define P push
#define I insert
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
const string abc="abcdefghijklmnopqrstuvwxyz";
const string ABC="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
const ll mod=1e9+7;
inline void io(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
void solve(){
io();
ll n,q,s,t;cin>>n>>q>>s>>t;
ll a[n+1];
ll b[n];
ll ans=0;
for(int i=0;i<=n;i++){
cin>>a[i];
if(i==0)continue;
b[i-1]=a[i]-a[i-1];
if(b[i-1]>0)ans-=s*(b[i-1]);
else ans-=t*b[i-1];
}
while(q--){
ll x,y,z;cin>>x>>y>>z;
if(b[x-1]>0)ans+=s*b[x-1];
else ans+=t*b[x-1];
b[x-1]+=z;
if(b[x-1]>0)ans-=s*b[x-1];
else ans-=t*b[x-1];
if(y==n){cout<<ans<<endl;continue;}
if(b[y]>0)ans+=s*b[y];
else ans+=t*b[y];
b[y]-=z;
if(b[y]>0)ans-=s*b[y];
else ans-=t*b[y];
cout<<ans<<endl;
}
}
int main(){
io();
solve();
//int t;cin>>t;for(int i=0;i<t;i++)solve();
return 0;
}
