#include <bits/stdc++.h>
using namespace std;
#define int long long
#define forinc(a, b, c) for(int a=b, _c=c; a<=_c; ++a)
#define fordec(a, b, c) for(int a=b, _c=c; a>=_c; --a)
#define forv(a, b) for(auto &a : b)
#define rep(i, n) forinc(i, 1, n)
#define repv(i, n) forinc(i, 0, n - 1)
#define ii pair<int,int>
#define fi first
#define se second
#define all(a) begin(a), end(a)
#define reset(f, x) memset(f, x, sizeof(f))
#define eb emplace_back
#define pb push_back
const int N = 3e5 + 5;
int n, q, s, t;
int a[N];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n >> q >> s >> t;
repv(i, n + 1) cin >> a[i];
int ans = 0;
function<void(int, int)> add = [&](int pos, int val) {
if(pos == n) return;
ans -= a[pos] * (a[pos] < 0 ? s : t);
a[pos] += val;
ans += a[pos] * (a[pos] < 0 ? s : t);
};
repv(i, n) {
int val = a[i] - a[i + 1]; a[i] = 0;
add(i, val);
}
while(q--) {
int l, r, val; cin >> l >> r >> val;
add(l - 1, -val); add(r, val);
cout << ans << '\n';
}
}
