#include <bits/stdc++.h>
using namespace std;
int _n;
const int mxN = 2e5+2;
long long st[4*mxN];
void update(int k, int x, int i = 1, int l = 0, int r = _n-1) {
if (l == r) {
st[i] += x;
return;
}
int mid = (l + r)/2;
if (k <= mid) {
update(k, x, 2*i, l, mid);
}
else {
update(k, x, 2*i+1, mid+1, r);
}
st[i] = st[2*i]+st[2*i+1];
}
long long query(int l, int r, int i = 1, int l2 = 0, int r2 = _n-1) {
if (l <= l2 && r2 <= r) {
return st[i];
}
int mid = (l2 + r2)/2;
long long s = 0;
if (l <= mid) {
s += query(l, r, 2*i, l2, mid);
}
if (mid+1 <= r) {
s += query(l, r, 2*i+1, mid+1, r2);
}
return s;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
long long n, q, s, t;
cin >> n >> q >> s >> t; _n = n+1;
vector<int> a(n+1);
long long sum = 0;
for (int i = 0; i <= n; ++i) {
cin >> a[i];
if (i) sum += (a[i] > a[i-1] ? -s*(a[i]-a[i-1]) : t*(a[i-1]-a[i]));
}
update(0, a[0]);
for (int i = 1; i <= n; ++i) {
update(i, a[i]-a[i-1]);
}
while (q--) {
int l, r, x;
cin >> l >> r >> x;
const long long lo1 = query(0, l-1), lo2 = query(0, l);
update(l, x);
sum -= (lo2 > lo1 ? -s*(lo2-lo1) : t*(lo1-lo2));
if (r != n) {
const long long ro1 = query(0, r), ro2 = query(0, r+1);
sum-=(ro2 > ro1 ? -s*(ro2-ro1) : t*(ro1-ro2));
update(r+1, -x);
}
const long long l1 = query(0, l-1), l2 = query(0, l);
if (r != n) {
const long long r2 = query(0, r+1), r1 = query(0, r);
sum+=(r2 > r1 ? -s*(r2-r1) : t*(r1-r2));
}
sum+=(l2 > l1 ? -s*(l2-l1) : t*(l1-l2));
cout << sum << '\n';
}
}
