#include <bits/stdc++.h>
#include <experimental/random>
#include <random>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;
using ld = long double;
using ll = long long;
const ll INF = 3e18, MOD = 1e9 + 7;
void solve();
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int q = 1;
//cin >> q;
while (q--) {
solve();
}
}
void solve() {
ll n, q, s, t;
cin >> n >> q >> s >> t;
vector<ll> a(n + 1);
for (int i = 0; i <= n; i++) cin >> a[i];
vector<ll> val(n + 1);
ll s1 = 0, s2 = 0;
for (int i = 1; i <= n; i++) {
val[i] = a[i] - a[i - 1];
if (val[i] < 0) s1 += val[i];
else s2 += val[i];
}
while (q--) {
ll l, r, x; cin >> l >> r >> x;
if (val[l] < 0) s1 -= val[l];
else s2 -= val[l];
val[l] += x;
if (val[l] < 0) s1 += val[l];
else s2 += val[l];
r++;
if (r <= n) {
if (val[r] < 0) s1 -= val[r];
else s2 -= val[r];
val[r] -= x;
if (val[r] < 0) s1 += val[r];
else s2 += val[r];
}
cout << -s1 * t - s2 * s << '\n';
}
}
