#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5 + 3, mod = 998244353;
int n, q, S, T, a[N];
ll ans;
ll get(int i) {
if (i > n) return 0;
if (a[i] > 0) return -1LL * a[i] * S;
return -1LL * a[i] * T;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
// freopen(".inp", "r", stdin);
// freopen(".out", "w", stdout);
cin >> n >> q >> S >> T;
for (int i = 0; i <= n; ++i) cin >> a[i];
for (int i = n; i >= 1; --i) {
a[i] -= a[i - 1];
ans += get(i);
}
// cout << ans << '\n';
while (q--) {
int l, r, x;
cin >> l >> r >> x;
ans -= get(l) + get(r + 1);
a[l] += x;
a[r + 1] -= x;
ans += get(l) + get(r + 1);
cout << ans << '\n';
}
}
