#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
using P = pair<int, int>;
#define all(x) x.begin(), x.end()
#define rep(i, l, n) for (int i = l; i < (n); ++i)
#define sz(x) (int)x.size()
const char nl = '\n';
const int mod = 1e9+7;
struct node {
int v, w, k;
};
void solve() {
int n, q, s, t; cin >> n >> q >> s >> t;
vector<int> a(n+1);
for (auto &i: a)cin >> i;
while (q--) {
int l, r, x; cin >> l >> r >> x;
rep(i, l, r+1)a[i] += x;
int cur = 0;
rep(i, 1, n+1) {
if (a[i-1] >= a[i])cur += (a[i-1]-a[i])*t;
else cur -= (a[i]-a[i-1])*s;
}
cout << cur << nl;
}
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
