#include <bits/stdc++.h>
using namespace std;
template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl
using ll = long long;
const int maxn = 1e6 + 5;
ll n,q,s,t;
ll a[maxn];
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>q>>s>>t;
for (int i=0; i<=n; i++) {
cin>>a[i];
}
++n;
while (q--) {
ll l,r,x;
cin>>l>>r>>x;
for (int i=l; i<=r; i++) {
a[i] += x;
}
ll res = 0;
for (int i=0; i+1<n; i++) {
if (a[i]<a[i+1]) {
res -= (a[i+1]-a[i])*s;
} else {
res += (a[i]-a[i+1])*t;
}
}
cout<<res<<"\n";
}
return 0;
}
