#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937 rnf(2106);
const int N = 200005;
int n, q;
ll S, T;
ll a[N];
ll t[N];
void ubd(int x, ll y)
{
while (x <= n)
{
t[x] += y;
x += (x & (-x));
}
}
ll qry(int x)
{
ll ans = 0;
while (x)
{
ans += t[x];
x -= (x & (-x));
}
return ans;
}
void solv()
{
cin >> n >> q >> S >> T;
for (int i = 0; i <= n; ++i)
cin >> a[i];
ll ans = 0;
for (int i = 0; i < n; ++i)
{
if (a[i] < a[i + 1])
ans += S * (a[i] - a[i + 1]);
else
ans += T * (a[i] - a[i + 1]);
}
for (int i = 1; i <= n; ++i)
{
ubd(i, a[i]);
ubd(i + 1, -a[i]);
}
while (q--)
{
int l, r;
ll y;
cin >> l >> r >> y;
if (qry(l - 1) < qry(l))
ans -= S * (qry(l - 1) - qry(l));
else
ans -= T * (qry(l - 1) - qry(l));
if (r < n)
{
if (qry(r) < qry(r + 1))
ans -= S * (qry(r) - qry(r + 1));
else
ans -= T * (qry(r) - qry(r + 1));
}
ubd(l, y);
ubd(r + 1, -y);
if (qry(l - 1) < qry(l))
ans += S * (qry(l - 1) - qry(l));
else
ans += T * (qry(l - 1) - qry(l));
if (r < n)
{
if (qry(r) < qry(r + 1))
ans += S * (qry(r) - qry(r + 1));
else
ans += T * (qry(r) - qry(r + 1));
}
cout << ans << "\n";
}
}
int main()
{
#ifdef SOMETHING
freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
#endif // SOMETHING
ios_base::sync_with_stdio(false), cin.tie(0);
int tt = 1;
//cin >> tt;
while (tt--)
{
solv();
}
return 0;
}
