#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
int n, q;
ll s, t;
ll a[200005] = { 0 };
ll sa[200005] = { 0 };
ll cdeg = 0;
int main() {
	cin >> n >> q >> s >> t;
	for (int i = 0; i <= n; i++) cin >> a[i];
	cdeg = 0;
	for (int i = 1; i <= n; i++) {
		sa[i] = a[i] - a[i - 1];
		//cout << sa[i] << endl;
		if (sa[i]>0) {
			cdeg -= s * sa[i];
			//cout << " " << s * sa[i] << endl;
		}
		if(sa[i]<0) {
			cdeg += t * abs(sa[i]);
			//cout << " " << t * abs(sa[i]) << endl;
		}
		//cout <<" "<< cdeg << endl;
	}
	for (int i = 0; i < q; i++) {
		int l, r;
		ll x;
		cin >> l >> r >> x;
		ll nl = sa[l] + x;
		ll a, b;
		if (sa[l]>0) a = -1 * s*sa[l];
		else a = abs(sa[l])*t;
		if (nl>0) b = -1 * s*nl;
		else b = abs(nl)*t;
		cdeg += (b - a);
		sa[l] = nl;
		if (r != n) {
			ll nr = sa[r + 1] - x;
			if (sa[r + 1]>0) a = -1 * s*sa[r + 1];
			else a = abs(sa[r + 1])*t;
			if (nr>0) b = -1 * s*nr;
			else b = abs(nr)*t;
			cdeg += (b - a);
			sa[r + 1] = nr;
		}
		cout << cdeg << endl;
	}
}

