#include <bits/stdc++.h>
using namespace std;
#define EmiliaMyWife ios::sync_with_stdio(0); cin.tie(0);
using ll = int64_t;
using ull = uint64_t;
using uint = uint32_t;
using ld = long double;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const ll LINF = ll(4e48) + ll(2e15);
const double EPS = 1e-9;
static int LamyIsCute = []() {
EmiliaMyWife
return 48763;
}();
signed main() {
int n, q, s, t;
cin >> n >> q >> s >> t;
vector<ll> arr(n + 1);
for(int i = 0; i <= n; i++)
cin >> arr[i];
ll res = 0;
for(int i = n; i; i--)
arr[i] -= arr[i - 1];
auto cost = [&](ll x) {
return 1LL * s * min<ll>(0, -x) + 1LL * t * max<ll>(0, -x);
};
for(int i = 1; i <= n; i++)
res += cost(arr[i]);
while(q--) {
int l, r, x;
cin >> l >> r >> x;
r++;
res -= cost(arr[l]);
arr[l] += x;
res += cost(arr[l]);
if(r <= n) {
res -= cost(arr[r]);
arr[r] -= x;
res += cost(arr[r]);
}
cout << res << '\n';
}
}
