#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define st first
#define nd second
#define pb push_back
const int MAXN = 1 << 19;
ll A, B;
ll dp[2 * MAXN];
ll ans = 0;
void upd(int l, int r, ll x) {
l += MAXN;
r += MAXN;
while (l < r) {
if (l % 2 == 1) {
dp[l] += x;
l++;
}
if (r % 2 == 0) {
dp[r] += x;
r--;
}
l /= 2;
r /= 2;
}
if (l == r) {
dp[l] += x;
}
}
ll query(int v) {
v += MAXN;
ll odp = 0;
while (v > 0) {
odp += dp[v];
v /= 2;
}
return odp;
}
ll policz(int i) {
ll X = query(i);
ll Y = query(i + 1);
// cout << "X = " << X << " Y = " << Y << '\n';
if (X < Y) {
return ((X - Y) * A);
}
return ((X - Y) * B);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int n, q;
cin >> n >> q >> A >> B;
n++;
ll x;
cin >> x;
upd(0, 0, x);
rep(i, n - 1) {
cin >> x;
upd(i + 1, i + 1, x);
// cout << policz(i) << '\n';
ans += policz(i);
}
// cout << "ans = " << ans << '\n';
while (q--) {
int l, r;
cin >> l >> r >> x;
if (l > 0) {
ans -= policz(l - 1);
}
if (r + 1 < n) {
ans -= policz(r);
}
upd(l, r, x);
if (l > 0) {
ans += policz(l - 1);
}
if (r + 1 < n) {
ans += policz(r);
}
cout << ans << '\n';
}
return 0;
}
