#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll N = 2e5 + 2;
ll T[16 * N], S[16 * N], a[N];
void Update(ll p, ll lo, ll hi, ll l, ll r, ll val) {
if (l > r) return ;
if ( lo > r || l > hi) return;
if ( l <= lo && hi <= r) {
S[p] += val;
return ;
}
ll mid = (lo + hi)/2;
Update(2 * p, lo, mid, l, r, val);
Update(2 * p + 1, mid + 1, hi, l, r, val);
}
ll val =0;
ll Find(ll p, ll lo, ll hi, ll x) {
val += S[p];
if ( lo == hi) {
val += a[lo];
return val;
}
ll mid = (lo +hi)/2;
if ( x <= mid) return Find(2 * p, lo, mid, x);
else return Find(2 * p + 1, mid + 1, hi, x);
}
int main() {
ll n,ans, t, up_price, i, x1, y1, x2, y2, lo, hi, x, down_price, deesh, doosh;
cin >> n >> t >> up_price >> down_price;
up_price *= -1;
deesh = doosh = 0;
for (i = 0; i <= n; i ++) {
cin >> a[i];
if (i == 0) continue;
if (a[i] > a[i- 1]) deesh += (a[i] - a[i - 1]);
else doosh += (a[i - 1] - a[i]);
}
while (t --) {
cin >> lo >> hi >> x;
val = 0;
x1 = Find(1, 0, n, lo - 1);
val = 0;
x2 = Find(1, 0, n, lo);
if ( x2 > x1) deesh -= (x2 - x1);
else doosh -= (x1 - x2);
if ( hi < n) {
val =0;
y1 = Find(1, 0, n, hi);
val = 0;
y2 = Find(1, 0, n, hi + 1);
if ( y2 > y1) deesh -= (y2 - y1);
else doosh -= (y1 - y2);
}
Update(1, 0, n, lo, hi, x);
val = 0;
x1 = Find(1, 0, n, lo - 1);
val = 0;
x2 = Find(1, 0, n, lo);
if ( x2 > x1) deesh += (x2 - x1);
else doosh += (x1 - x2);
if ( hi < n) {
val =0;
y1 = Find(1, 0, n, hi);
val = 0;
y2 = Find(1, 0, n, hi + 1);
if ( y2 > y1) deesh += (y2 - y1);
else doosh += (y1 - y2);
}
ans = doosh * down_price + deesh * up_price;
cout << ans << endl;
}
}
