#include <bits/stdc++.h>
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define FOD(i, a, b) for(int i = (a); i >= (b); i--)
#define file(name) if(fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define el cout << '\n'
#define maxn int(2e5 + 5)
using namespace std;
typedef long long ll;
int n, q, S, T;
ll a[maxn];
namespace subtask1 {
bool check() {
return n <= 2000;
}
void solve() {
while(q--) {
ll res = 0;
int l, r, x;
cin >> l >> r >> x;
FOR(i, l, r) a[i] += x;
FOR(i, 1, n) {
if(a[i] > a[i - 1]) res -= 1LL * S * abs(a[i] - a[i - 1]);
else res += 1LL * T * abs(a[i] - a[i - 1]);
}
cout << res, el;
}
}
}
namespace subtask3 {
ll d[maxn];
ll t[maxn << 2];
void update(int pos, ll val, int id = 1, int l = 1, int r = n) {
if(pos < l || r < pos) return;
if(l == r) {
t[id] = val;
return;
}
int mid = (l + r) >> 1;
update(pos, val, id << 1, l, mid);
update(pos, val, id << 1 | 1, mid + 1, r);
t[id] = t[id << 1] + t[id << 1 | 1];
}
void updatePoint(int i) {
if(d[i] > 0) update(i, -1LL * S * abs(d[i]));
else update(i, 1LL * T * abs(d[i]));
}
void solve() {
FOR(i, 1, n) {
d[i] = a[i] - a[i - 1];
updatePoint(i);
}
while(q--) {
int l, r, x;
cin >> l >> r >> x;
d[l] += x;
d[r + 1] -= x;
updatePoint(l);
if(r + 1 <= n) updatePoint(r + 1);
cout << t[1], el;
}
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> q >> S >> T;
FOR(i, 0, n) cin >> a[i];
if(subtask1::check()) return subtask1::solve(), 0;
return subtask3::solve(), 0;
return 0;
}
