#include <iostream>
using namespace std;
#define ll long long
const int MAX = 2e5 + 7;
ll bit[MAX];
inline void add(int x, ll val)
{
for (int i = x; i < MAX; i += (i & -i))
bit[i] += val;
}
inline ll sum(int x)
{
ll res = 0;
for (int i = x; i > 0; i -= (i & -i))
res += bit[i];
return res;
}
ll n, q, s, t, val = 0;
inline void in(int i)
{
ll x = sum(i) - sum(i-1);
if (x >= 0) val -= s*x;
else val -= t*x;
}
inline void out(int i)
{
ll x = sum(i) - sum(i-1);
if (x >= 0) val += s*x;
else val += t*x;
}
int main()
{
ios :: sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; ++i)
{
ll x; cin >> x;
if (i)
{
add(i, x - sum(i-1));
in(i);
}
}
while (q--)
{
int l, r, k;
cin >> l >> r >> k;
out(l); if (r < n) out(r+1);
add(l, k);
add(r+1, -k);
in(l); if (r < n) in(r+1);
cout << val << '\n';
}
return 0;
}
