#include <bits/stdc++.h>
#define IO_OP ios::sync_with_stdio(0), cin.tie(0)
#define F first
#define S second
#define V vector
#define PB push_back
#define EB emaplce_back
#define MP make_pair
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef vector<int> vi;
const int INF = 1e9 + 7, N = 2e5 + 7;
int a[N];
ll d[N];
signed main()
{
IO_OP;
int n, q, s, t;
cin >> n >> q >> s >> t;
ll ans = 0;
auto cost = [&] (ll x) {
if(x > 0) return -x * s;
else return -x * t;
};
for(int i = 0; i < n + 1; i++) {
cin >> a[i];
if(i) {
d[i] = a[i] - a[i - 1];
ans += cost(d[i]);
}
}
for(int i = 0; i < q; i++) {
int l, r, x;
cin >> l >> r >> x;
// d[l] += x, d[r + 1] -= x
ans -= cost(d[l]);
d[l] += x;
ans += cost(d[l]);
if(r + 1 <= n) {
ans -= cost(d[r + 1]);
d[r + 1] -= x;
ans += cost(d[r + 1]);
}
cout << ans << '\n';
}
}
