#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define int long long
#define all(v) v.begin(), v.end()
using namespace std;
const int mxn = 1e6 + 5, mod = 1e9 + 7, inf = 1e18;
int a[mxn], seg[4 * mxn];
void update(int u, int l, int r, int k, int v) {
if (k < l || k > r) return;
if (l == r) {seg[u] += v; return;}
int mid = (l + r) / 2;
update(u * 2, l, mid, k, v);
update(u * 2 + 1, mid + 1, r, k, v);
seg[u] = seg[u * 2] + seg[u * 2 + 1];
}
int ask(int u, int l, int r, int ql, int qr) {
if (l > qr || r < ql) return 0;
if (l >= ql && r <= qr) return seg[u];
int mid = (l + r) / 2;
int left = ask(u * 2, l, mid, ql, qr);
int right = ask(u * 2 + 1, mid + 1, r, ql, qr);
return left + right;
}
void solve() {
int n, q, s, t;
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) {
cin >> a[i];
}
vector<int> d;
for (int i = 1; i <= n; i++) {
d.pb(a[i] - a[i - 1]);
}
vector<int> res(n + 1);
for (int i = 0; i < n; i++) {
if (d[i] > 0) res[i] = -s * d[i];
else res[i] = t * (-d[i]);
}
for (int i = 1; i <= n; i++) {
res[i] += res[i - 1];
}
int ans = res[n];
while (q--) {
int l, r, x;
cin >> l >> r >> x;
int al = a[l] + ask(1, 1, n, 0, l);
int ar = a[r] + ask(1, 1, n, 0, r);
int al_1 = a[l - 1] + ask(1, 1, n, 0, l - 1);
int ar_1 = a[r + 1] + ask(1, 1, n, 0, r + 1);
if (al - al_1 > 0) {
ans -= -s * (al - al_1);
}
else {
ans -= t * (al_1 - al);
}
if (r != n) {
if (ar_1 - ar > 0) {
ans -= -s * (ar_1 - ar);
}
else {
ans -= t * (ar - ar_1);
}
}
update(1, 1, n, l, x);
if (r != n)update(1, 1, n, r + 1, -x);
al = a[l] + ask(1, 1, n, 0, l);
ar = a[r] + ask(1, 1, n, 0, r);
al_1 = a[l - 1] + ask(1, 1, n, 0, l - 1);
ar_1 = a[r + 1] + ask(1, 1, n, 0, r + 1);
if (al - al_1 > 0) {
ans += -s * (al - al_1);
}
else {
ans += t * (al_1 - al);
}
if (r != n) {
if (ar_1 - ar > 0) {
ans += -s * (ar_1 - ar);
}
else {
ans += t * (ar - ar_1);
}
}
cout << ans << '\n';
}
}
//
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr);
int t = 1;
//cin >> t;
while (t--) {
solve();
}
}
