#include <bits/stdc++.h>
#define sts(v) stable_sort(v.BE, v.E)
#define Rsts(v) stable_sort(v.rBE, v.rE)
#define rev(v) reverse(v.BE, v.E)
#define BE begin()
#define rBE rbegin()
#define E end()
#define rE rend()
#define pb push_back
#define ppb pop_back()
#define pf push_front
#define ppf pop_front()
#define F first
#define S second
using namespace std;
using ll = long long;
struct datos{
int val, w, k;
};
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n, Q, S, T; cin >> n >> Q >> S >> T;
vector<int> v(n + 1);
for(int i = 0; i <= n; i++)
cin >> v[i];
while(Q--){
int l, r, x; cin >> l >> r >> x;
if(S == T){
if(r == n)v[n] += x;
cout << -(v[n] * S) << '\n';
}else{
while(l <= r){
v[l] += x;
l++;
}
ll Temp[n + 1];
Temp[0] = 0;
for(int i = 1; i <= n; i++){
Temp[i] = Temp[i - 1];
if(v[i] > v[i - 1])
Temp[i] -= S * (v[i] - v[i - 1]);
else
Temp[i] += T * (v[i - 1] - v[i]);
}
cout << Temp[n] << '\n';
}
}
return 0;
}
