#include <bits/stdc++.h>
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define rall(x) x.rbegin(), x.rend()
#define int long long
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
const double eps = 1e-9;
void setIO() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
}
int32_t main() {
setIO();
int n, q, s, t;
ll ans = 0;
cin >> n >> q >> s >> t;
vector<int> v(n+1);
vector<int> diff(n+1);
for(int i=0; i<=n; i++) {
cin >> v[i];
if(i > 0) {
diff[i] = v[i] - v[i-1];
if(diff[i] > 0) ans -= (diff[i] * s);
else ans += (abs(diff[i]) * t);
}
}
while(q--) {
int l, r, x;
cin >> l >> r >> x;
if(diff[l] > 0) ans += (diff[l] * s);
else ans -= (abs(diff[l]) * t);
diff[l] += x;
if(diff[l] > 0) ans -= (diff[l] * s);
else ans += (abs(diff[l]) * t);
if(r != n) {
if(diff[r+1] > 0) ans += (diff[r+1] * s);
else ans -= (abs(diff[r+1]) * t);
diff[r+1] -= x;
if(diff[r+1] > 0) ans -= (diff[r+1] * s);
else ans += (abs(diff[r+1]) * t);
}
cout << ans << '\n';
}
return 0;
}
