#include "bits/stdc++.h"
#define int long long
using namespace std;

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int n, q, s, t;
    cin >> n >> q >> s >> t;
    vector<int> a(n + 1);
    for (int i = 0; i <= n; i++) {
        cin >> a[i];
    }
    
    vector<int> b(n);

    int sum0 = 0;
    int sum1 = 0;

    auto change = [&](int i, int x) {
        if (b[i] < 0) {
            sum0 -= b[i];
        } else {
            sum1 -= b[i];
        }
        b[i] += x;
        if (b[i] < 0) {
            sum0 += b[i];
        } else {
            sum1 += b[i];
        }
    };

    for (int i = 0; i < n; i++) {
        change(i, a[i + 1] - a[i]);
    }

    for (int j = 0; j < q; j++) {
        int l, r, x;
        cin >> l >> r >> x;

        change(l - 1, x);

        if (r != n) {
            change(r, -x);
        }

        cout << -sum0 * t - sum1 * s << '\n';
    }
    return 0;
}