//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#include<bits/stdc++.h>
using namespace std;
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(a) (int)a.size()
#define s second
#define f first
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<pii> rid = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
vector<pii> dir = {{-1, -1}, {-1, 1}, {1, -1}, {1, 1}};
const int N = 5e6 + 1, mod = 998244353;
const ll inf = 1e9;
double eps = 1e-15;
bool flg = 0;
void slv() {
int n, q, s, t;
cin >> n >> q >> s >> t;
ll a[n + 1], b[n + 1];
cin >> a[0];
ll ans = 0;
for (int i = 1; i <= n; i++) {
cin >> a[i];
b[i] = a[i] - a[i - 1];
if (b[i] > 0) ans -= s * b[i];
else ans -= t * b[i];
}
while (q--) {
int l, r, x;
cin >> l >> r >> x;
if (b[l] > 0) ans += s * b[l];
else ans += t * b[l];
b[l] += x;
if (b[l] > 0) ans -= s * b[l];
else ans -= t * b[l];
if (r < n) {
if (b[r + 1] > 0) ans += s * b[r + 1];
else ans += t * b[r + 1];
b[r + 1] -= x;
if (b[r + 1] > 0) ans -= s * b[r + 1];
else ans -= t * b[r + 1];
}
cout << ans << '\n';
}
}
main() {
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
int tp = 1;
if (flg) cin >> tp;
while (tp--) {
slv();
}
}
//wenomechainsama
