#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44
using namespace std;
struct Fenwick {
vector <ll> aib;
int n;
inline void init(int _n) {
n = _n;
aib.resize(n + 1, 0);
}
inline void update(int pos, int val) {
for(int i = pos; i <= n; i += lsb(i)) {
aib[i] += val;
}
}
inline ll query(int pos) {
ll ans = 0;
for(int i = pos; i > 0; i -= lsb(i)) {
ans += aib[i];
}
return ans;
}
};
inline ll get(ll h1, ll h2, int s, int t) {
if(h1 < h2) return -1LL * (h2 - h1) * s;
return 1LL * (h1 - h2) * t;
}
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i, n, q, s, t;
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n >> q >> s >> t;
ll cur = 0;
vector <int> a(n + 2);
for(i = 1; i <= n + 1; i++) {
cin >> a[i];
if(i > 1) {
cur += get(a[i - 1], a[i], s, t);
}
}
Fenwick fen; fen.init(n + 1);
while(q > 0) {
q--;
int l, r, x;
cin >> l >> r >> x;
l++, r++;
if(l > 1) {
cur -= get(a[l - 1] + fen.query(l - 1), a[l] + fen.query(l), s, t);
}
if(r <= n) {
cur -= get(a[r] + fen.query(r), a[r + 1] + fen.query(r + 1), s, t);
}
fen.update(l, x);
fen.update(r + 1, -x);
if(l >= 1) {
cur += get(a[l - 1] + fen.query(l - 1), a[l] + fen.query(l), s, t);
}
if(r <= n) {
cur += get(a[r] + fen.query(r), a[r + 1] + fen.query(r + 1), s, t);
}
cout << cur << "\n";
}
//cin.close();
//cout.close();
return 0;
}
