#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define debug(x) cerr << #x << ' ' << x << '\n'
#define endl '\n'
using namespace std;
const int M = 1e9 + 7;
typedef long long ll;
struct BIT {
int N;
vector<ll> v;
BIT(int N): N(N + 1), v(N + 2) {}
inline int lb(int x) {
return x & -x;
}
void update(int i, ll dx) {
for (; i <= N; i += lb(i)) v[i] += dx;
}
ll query(int i) {
ll ans = 0;
for (; i; i -= lb(i)) ans += v[i];
return ans;
}
};
int main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int N, Q, S, T;
cin >> N >> Q >> S >> T;
vector<ll> h(N + 1);
for (auto& n: h) cin >> n;
BIT bit(N);
ll current = 0;
for (int i = 1; i <= N; i++) {
if (h[i] > h[i - 1]) {
current -= (h[i] - h[i - 1]) * S;
} else {
current -= (h[i] - h[i - 1]) * T;
}
bit.update(i, h[i] - h[i - 1]);
}
// for (auto& n: bit.v) cerr << n << " \n"[&n == &bit.v.back()];
for (int i = 0; i <= N; i++) {
// cerr << bit.query(i) << ' ';
}
// cerr << '\n';
ll l, r, dy;
for (int i = 0; i < Q; i++) {
cin >> l >> r >> dy;
ll h1, h2, h3, h4;
h1 = bit.query(l - 1);
h2 = bit.query(l);
h3 = bit.query(r);
h4 = bit.query(r + 1);
if (h2 > h1) {
current += (h2 - h1) * S;
} else {
current += (h2 - h1) * T;
}
if (r != N && h4 > h3) {
current += (h4 - h3) * S;
} else if (r != N && h4 <= h3) {
current += (h4 - h3) * T;
}
bit.update(l, dy);
bit.update(r + 1, -dy);
h1 = bit.query(l - 1);
h2 = bit.query(l);
h3 = bit.query(r);
h4 = bit.query(r + 1);
current -= (h2 > h1 ? S : T) * (h2 - h1);
if (r != N) current -= (h4 > h3 ? S : T) * (h4 - h3);
cout << current << '\n';
}
return 0;
}
