#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 200005;
int n, q; ll s, t;
// n <= 2000 && q <= 2000
namespace sub1 {
ll alti[N], temp[N];
void Main() {
for (int i = 0; i <= n; i++) {
cin >> alti[i];
}
while (q--) {
int l, r; ll x;
cin >> l >> r >> x;
for (int i = l; i <= r; i++) {
alti[i] += x;
}
for (int i = 1; i <= n; i++) {
if (alti[i - 1] < alti[i]) {
temp[i] = temp[i - 1] - s * (alti[i] - alti[i - 1]);
}
else {
temp[i] = temp[i - 1] + t * (alti[i - 1] - alti[i]);
}
}
cout << temp[n] << '\n';
}
}
}
// s == t
namespace sub2 {
ll alti[N];
void Main() {
for (int i = 0; i <= n; i++) {
cin >> alti[i];
}
while (q--) {
int l, r; ll x;
cin >> l >> r >> x;
if (r == n) alti[n] += x;
cout << alti[n] * (-t) << '\n';
}
}
}
struct Bit {
vector<ll> bit;
Bit(int n): bit(n + 1) {}
void update(int i, ll v) {
for (; i < (int) bit.size(); i += i & -i) {
bit[i] += v;
}
}
ll get(int i) {
ll v = 0;
for (; i; i -= i & -i) {
v += bit[i];
}
return v;
}
};
namespace sub3 {
ll a[N], diff[N];
void updDiff(Bit &alti, int p) {
if (p > n) return;
diff[p] = alti.get(p) - alti.get(p - 1);
}
void addAns(ll &ans, int p) {
if (p > n) return;
if (diff[p] > 0) ans -= s * diff[p];
else ans += t * (-diff[p]);
}
void remAns(ll &ans, int p) {
if (p > n) return;
if (diff[p] > 0) ans += s * diff[p];
else ans -= t * (-diff[p]);
}
void Main() {
ll ans = 0;
Bit alti(n + 1);
for (int i = 0; i <= n; i++) {
cin >> a[i];
if (i > 0) {
diff[i] = a[i] - a[i - 1];
alti.update(i, diff[i]);
if (diff[i] > 0) ans -= s * diff[i];
else ans += t * (-diff[i]);
}
}
while (q--) {
int l, r; ll x;
cin >> l >> r >> x;
remAns(ans, l);
remAns(ans, r + 1);
alti.update(l, x);
alti.update(r + 1, -x);
updDiff(alti, l);
updDiff(alti, r + 1);
addAns(ans, l);
addAns(ans, r + 1);
cout << ans << '\n';
}
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> q >> s >> t;
if (n <= 2000 && q <= 2000) sub1::Main();
else if (s == t) sub2::Main();
else sub3::Main();
}
