#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 200005;
int n, q, s, t, a[N], ans, rem[N];
void upd1 (int l) {
if (rem[l] > 0) ans += s * rem[l];
else ans += t * rem[l];
}
void upd2 (int l) {
if (rem[l] > 0) ans -= s * rem[l];
else ans -= t * rem[l];
}
signed main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; ++i) {
cin >> a[i];
if (i) {
rem[i] = a[i] - a[i - 1];
if (a[i] > a[i - 1]) ans -= s * (a[i] - a[i - 1]);
else ans += t * (a[i - 1] - a[i]);
}
}
while (q--) {
int l, r, _x; cin >> l >> r >> _x;
upd1 (l);
if (r < n) {
upd1 (r + 1);
}
rem[l] += _x;
if (r < n) {
rem[r + 1] -= _x;
}
upd2 (l);
if (r < n) {
upd2 (r + 1);
}
cout << ans << '\n';
}
return 0;
}
