#include <bits/stdc++.h>
//#include "factories.h"
#define f first
#define s second
#define int long long
using namespace std;
const int maxn = 2e5 + 69;
long long n, q, s, t, a[maxn], st[4 * maxn], f[maxn];
void upd(int v, int tl, int tr, int x, int d) {
if(tl == tr)
st[v] = d;
else {
int mid = (tl + tr) / 2;
if(x <= mid)
upd(v * 2, tl, mid, x, d);
else
upd(v * 2 + 1, mid + 1, tr, x, d);
st[v] = st[v * 2] + st[v * 2 + 1];
}
}
void add(int v, int d) {
for(int i = v;i < maxn;i += (i & -i))
f[i] += d;
}
int qry(int v) {
int res = 0;
for(int i = v;i >= 1;i -= (i & -i))
res += f[i];
return res;
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while(tt--) {
cin >> n >> q >> s >> t;
for(int i = 0;i <= n;i++)
cin >> a[i];
for(int i = 1;i <= n;i++) {
if(a[i] > a[i - 1])
upd(1, 1, n, i, (a[i - 1] - a[i]) * s);
else
upd(1, 1, n, i, (a[i - 1] - a[i]) * t);
}
for(int i = 1;i <= q;i++) {
int l, r, x;
cin >> l >> r >> x;
add(l, x);
add(r + 1, -x);
int levi = a[l] + qry(l);
int desni = a[r] + qry(r);
int kurac = 0;
int josjedankurac = 0;
if(l > 1)
kurac = a[l - 1] + qry(l - 1);
if(r < n)
josjedankurac = a[r + 1] + qry(r + 1);
if(levi > kurac)
upd(1, 1, n, l, (kurac - levi) * s);
else
upd(1, 1, n, l, (kurac - levi) * t);
if(r < n) {
if(josjedankurac > desni)
upd(1, 1, n, r + 1, (desni - josjedankurac) * s);
else
upd(1, 1, n, r + 1, (desni - josjedankurac) * t);
}
cout << st[1] << "\n";
}
}
return 0;
}
