#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
void Solve()
{
int n, q, s, t;
cin >> n >> q >> s >> t;
vector <int> a(n + 1), d(n);
int c1 = 0, c2 = 0;
for (int i = 0; i <= n; i++){
cin >> a[i];
if (i != 0) {
d[i - 1] = a[i] - a[i - 1];
if (d[i - 1] > 0) c1 += d[i - 1];
else c2 += d[i - 1];
}
}
s = -s;
while (q--){
int l, r, k; cin >> l >> r >> k;
if (d[l - 1] > 0) c1 -= d[l - 1];
else c2 -= d[l - 1];
d[l - 1] += k;
if (d[l - 1] > 0) c1 += d[l - 1];
else c2 += d[l - 1];
if (r != n){
if (d[r] > 0) c1 -= d[r];
else c2 -= d[r];
d[r] -= k;
if (d[r] > 0) c1 += d[r];
else c2 += d[r];
}
cout << c1 * s - c2 * t << "\n";
}
}
int32_t main()
{
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
