#include <bits/stdc++.h>
#include <random>
using namespace std;
using ll = long long;
using ld = long double;
ll INF = 1e18;
vector<pair<ll, ll>> tree;
vector<ll> z;
void build(ll v, ll vl, ll vr) {
if (vr - vl == 1) {
if (z[vl] < 0) {
tree[v].second = z[vl];
} else {
tree[v].first = z[vl];
}
return;
}
ll mid = (vr + vl) / 2;
build(v * 2, vl, mid);
build(v * 2 + 1, mid, vr);
tree[v].second = tree[v * 2].second + tree[v * 2 + 1].second;
tree[v].first = tree[v * 2].first + tree[v * 2 + 1].first;
}
void change(ll v, ll vl, ll vr, ll ind, ll x) {
if (vr - vl == 1) {
z[vl] += x;
tree[v].second = 0;
tree[v].first = 0;
if (z[vl] < 0) {
tree[v].second = z[vl];
} else {
tree[v].first = z[vl];
}
return;
}
ll mid = (vr + vl) / 2;
if (ind < mid) {
change(v * 2, vl, mid, ind, x);
} else {
change(v * 2 + 1, mid, vr, ind, x);
}
tree[v].second = tree[v * 2].second + tree[v * 2 + 1].second;
tree[v].first = tree[v * 2].first + tree[v * 2 + 1].first;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
ll n, q, s, t;
cin >> n >> q >> s >> t;
ll a;
cin >> a;
for (ll i = 1; i < n + 1; i++) {
ll b;
cin >> b;
z.push_back({b - a});
a = b;
}
tree.assign(n * 4, {});
build(1, 0, n);
for (ll i = 0; i < q; i++) {
ll v1, v2, v3;
cin >> v1 >> v2 >> v3;
change(1, 0, n, v1 - 1, v3);
if (n != v2) {
change(1, 0, n, v2, -v3);
}
cout << -tree[1].first * s - tree[1].second * t << endl;
}
}
