#include<bits/stdc++.h>
using namespace std;
#define ll long long
// s min t plus
// kanan lebih tinggi -> min, kiri lebih tinggi -> plus
// baru nyadar ini O(n*q) wkwk tle deh
ll n, q, s, t;
ll h[200005];
int main(){
cin>>n>>q>>s>>t;
for (int i = 0; i <= n; ++i){
cin>>h[i];
}
for (int i = 0; i < q; ++i){
ll lidx, ridx, w;
cin>>lidx>>ridx>>w;
ll scnt = 0;
ll tcnt = 0;
for (int j = lidx; j <= ridx; ++j){
h[j] += w;
}
for (int j = 0; j < n ; ++j){
if (h[j+1] >= h[j]){
scnt -= h[j+1] - h[j];
} else {
tcnt += h[j] - h[j+1];
}
}
// for (int j = 0; j <= n ; ++j){
// if (j==n){
// cout<<h[j]<<endl;
// } else {
// cout<<h[j]<<" ";
// }
// }
// cout<<"scnt = "<<scnt<<" "<<"tcnt ="<<tcnt<<endl;
cout<<(s*scnt) + (t*tcnt)<<endl;
}
}
