#include <bits/stdc++.h>
using namespace std;
#define db(val) "[" #val " = " << (val) << "] "
const int maxn = 2e5 + 4;
const int mod = 1e9 + 7;
int n, q, s, t, a[maxn], bit[maxn];
void updatePoint(int u, int v) {
int idx = u;
while (idx <= n) {
bit[idx] += v;
idx += (idx & (-idx));
}
}
void updateRange(int l, int r, int v) {
updatePoint(l, v);
updatePoint(r + 1, -v);
}
int get(int u) {
if (u == 0) return a[0];
if (u == n + 1) u = n;
int idx = u, ans = 0;
while (idx > 0) {
ans += bit[idx];
idx -= (idx & (-idx));
}
return ans;
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("inputf.in", "r", stdin);
cin >> n >> q >> s >> t;
int sum = 0;
for (int i = 0; i <= n; i++) {
cin >> a[i];
if (i > 0) {
updateRange(i, i, a[i]);
int dif = a[i] - a[i - 1];
sum -= dif * (dif > 0 ? s : t);
}
}
while (q--) {
int l, r, k; cin >> l >> r >> k;
int dif;
dif = get(l) - get(l - 1);
sum += dif * (dif > 0 ? s : t);
dif = get(r + 1) - get(r);
// clog << db(r) << db(r + 1) << dif << '\n';
sum += dif * (dif > 0 ? s : t);
updateRange(l, r, k);
dif = get(l) - get(l - 1);
sum -= dif * (dif > 0 ? s : t);
dif = get(r + 1) - get(r);
sum -= dif * (dif > 0 ? s : t);
cout << sum << '\n';
}
}
