#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) { cerr << to_string(h); if(sizeof...(t)) cerr << ", "; DBG(t...); }
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
const int N = 2003;
ll a[N];
void solve() {
ll n, q, s, t; cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) cin >> a[i];
while (q--) {
ll l, r, x; cin >> l >> r >> x;
for (int j = l; j <= r; j++)
a[j] += x;
ll ans = 0;
for (int i = 1; i <= n; i++) {
if (a[i-1] < a[i])
ans -= (a[i]-a[i-1])*s;
else
ans += (a[i-1]-a[i])*t;
}
cout << ans << "\n";
}
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0);
int t=1; //cin >> t;
while (t--) {
solve();
}
}
