#include <bits/stdc++.h>
#define pb push_back
#define all(v) v.begin(), v.end()
#define sz(v) int(v.size())
#define pii pair<int, int>
#define mp make_pair
#define f first
#define ll long long
#define ld long double
#define s second
#define vec vector<int>
using namespace std;
const int N = (int) 2e5 + 10;
const int M = (int) 2018 * 2018;
const int K = (int) 15;
const int INF = (int) 1e9 + 7;
const int mod = (int) 998244353;
const ld EPS = (ld) 1e-9;
const ll LINF = (ll) 1e18;
int n, q;
ll s, t;
ll a[N], b[N];
ll sum;
void upd(int id, int val) {
if (b[id] > 0) {
sum += b[id] * s;
} else {
sum += b[id] * t;
}
b[id] += val;
if (b[id] > 0) {
sum -= b[id] * s;
} else {
sum -= b[id] * t;
}
}
int main() {
#ifdef sony
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
srand(time(0));
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) {
cin >> a[i];
}
for (int i = 1; i <= n; i++) {
upd(i, a[i] - a[i - 1]);
}
while (q--) {
int l, r, x;
cin >> l >> r >> x;
upd(l, x);
if (r < n)
upd(r + 1, -x);
cout << sum << endl;
}
return 0;
}
