#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math")
//#pragma GCC target("avx,avx2,fma")
using namespace std;
#define ll int
#define sped_up ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define rall(v) (v).rbegin(), (v).rend()
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define S second
#define F first
const ll INF = (ll)1e9 + 1, INFL = (ll)1e18 + 1;
const ll mod = (ll)1e9 + 7, MAXN = (ll)2e5 + 1;
ll a[MAXN], t[MAXN * 4];
void build (ll v, ll tl, ll tr) {
if (tl == tr) t[v] = a[tl];
if (tl == tr) return;
ll tm = (tl + tr) / 2;
build (v * 2, tl, tm);
build (v * 2 + 1, tm + 1, tr);
t[v] = 0;
}
ll get (ll v, ll tl, ll tr, ll i) {
if (tl == tr) return t[v];
ll tm = (tl + tr) / 2;
if (i <= tm) return t[v] + get(v * 2, tl, tm, i);
else return t[v] + get(v * 2 + 1, tm + 1, tr, i);
}
void upd (ll v, ll tl, ll tr, ll l, ll r, ll x) {
if (l <= tl && tr <= r) t[v] += x;
if (l <= tl && tr <= r) return;
if (l > tr || tl > r) return;
ll tm = (tl + tr) / 2;
upd (v * 2, tl, tm, l, r, x);
upd (v * 2 + 1, tm + 1, tr, l, r, x);
}
int main() {
sped_up;
ll n, q, s, t;
cin >> n >> q >> s >> t;
ll cnt = 0;
for (int i = 0; i <= n; i++) {
cin >> a[i];
if (i != 0) {
if (a[i] > a[i - 1]) cnt -= s * (a[i] - a[i - 1]);
else cnt -= t * (a[i] - a[i - 1]);
}
}
build (1, 0, n);
while (q--) {
ll L, R, x;
cin >> L >> R >> x;
ll r1 = 0;
ll l = get(1, 0, n, L);
ll r = get(1, 0, n, R);
ll l1 = get(1, 0, n, L - 1);
if (r != n) r1 = get(1, 0, n, R + 1);
else r1 = r;
if (l > l1) cnt += s * (l - l1);
else cnt += t * (l - l1);
if (r1 > r) cnt += s * (r1 - r);
else cnt += t * (r1 - r);
upd (1, 0, n, L, R, x);
r1 = 0;
l = get(1, 0, n, L);
r = get(1, 0, n, R);
l1 = get(1, 0, n, L - 1);
if (R != n) r1 = get(1, 0, n, R + 1);
else r1 = r;
if (l > l1) cnt -= s * (l - l1);
else cnt -= t * (l - l1);
if (r1 > r) cnt -= s * (r1 - r);
else cnt -= t * (r1 - r);
cout << cnt << '\n';
}
}
