#include <bits/stdc++.h>
#include <iostream>
#define ll long long
#define endl '\n'
#define pll pair<ll,ll>
#define fi first
#define se second
using namespace std;
ll n, q, s, t, l ,r, x, j[200007], sum[200007], ans;
//def WA lol
int main(){
cin>>n>>q>>s>>t;
for(int i = 0; i <= n; i++){
cin>>j[i];
}
for(int i = 1; i <= n; i++){
cout<<"TEST\n";
ll d = j[i] - j[i-1];
if(d > 0){
sum[i] = sum[i-1] - d*s;
}
else if(d < 0){
sum[i] = sum[i-1] - d*t;
}
else sum[i] = sum[i-1];
}
// for(int i = 0; i <= n; i++){
// cout<<sum[i]<<" ";
// }
ll b = sum[n];
while(q--){
cin>>l>>r>>x;
ll dl = j[l] - j[l-1];
j[l] += x;
if(dl > 0){
b -= dl*s;
}
else if(dl < 0){
b -= dl*t;
}
if(r < n){
ll dr = j[r] - j[r-1];
if(dr > 0){
b -= dr*s;
}
else if(dr < 0){
b -= dr*t;
}
}
cout<<b<<endl;
}
}
