#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const int MAX = 200007;
ll A[MAX], d, u;
void Change(int i, ll n) {
(A[i] < 0 ? d += A[i] : u -= A[i]);
A[i] += n;
(A[i] < 0 ? d -= A[i] : u += A[i]);
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
ll N, Q, S, T;
cin >> N >> Q >> S >> T;
for (int i = 0; i <= N; ++i) cin >> A[i];
for (int i = N; i > 0; --i) A[i] = A[i] = A[i] - A[i - 1];
for (int i = 1; i <= N; ++i) {
if (A[i] >= 0) u += A[i];
else d -= A[i];
}
while (Q--) {
ll l, r, n;
cin >> l >> r >> n;
Change(l, n);
if (r != N) Change(r + 1, -n);
cout << d * T - u * S << '\n';
}
return 0;
}
