#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;
int main() {
cin.tie(0) -> sync_with_stdio(0);
int n, q, s, t;
cin >> n >> q >> s >> t;
vector<ll> A(n + 1);
for (int i = 0; i <= n; i++) {
cin >> A[i];
}
vector<ll> diff(n);
ll res = 0;
for (int i = 0; i < n; i++) {
diff[i] = A[i + 1] - A[i];
if (diff[i] > 0) {
res -= s * diff[i];
} else {
res += t * (-diff[i]);
}
}
// cout << res << "\n";
while (q--) {
int L, R;
ll k;
cin >> L >> R >> k;
int idx = L - 1;
if (diff[idx] > 0)
res += s * diff[idx];
else
res -= t * (-diff[idx]);
diff[idx] += k;
if (diff[idx] > 0)
res -= s * diff[idx];
else
res += t * (-diff[idx]);
if (R < n) {
idx = R;
if (diff[idx] > 0)
res += s * diff[idx];
else
res -= t * (-diff[idx]);
diff[idx] -= k;
if (diff[idx] > 0)
res -= s * diff[idx];
else
res += t * (-diff[idx]);
}
cout << res << "\n";
}
return 0;
}
