#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
#define int long long
typedef long long ll;
ll bit[maxn], v[maxn], n, q, s, t, ans;
ll calc(ll a, ll b)
{
if(a < b) return -s*(abs(a - b));
else return t*(abs(a - b));
}
void update(int id, ll val)
{
for(int i = id; i <= n; i += i&-i)
{
bit[i] += val;
}
}
int query(int id)
{
ll ans = 0;
for(int i = id; i > 0; i -= i&-i)
{
ans += bit[i];
}
return ans;
}
int32_t main()
{
ios::sync_with_stdio(false), cin.tie(nullptr);
cin >> n >> q >> s >> t;
for(int i = 0; i <= n; i++)
{
cin >> v[i];
if(i > 0) update(i, v[i]), update(i + 1, -v[i]);
}
for(int i = 0; i < n; i++)
ans += calc(v[i], v[i + 1]);
while(q--)
{
ll l, r, x;
cin >> l >> r >> x;
ll a, b, c, d;
a = query(l - 1);
b = query(l);
c = query(r);
d = query(r + 1);
ans -= calc(a, b);
if(r < n) ans -= calc(c, d);
update(l, x);
update(r + 1, -x);
ans += (calc(a, b + x));
if(r < n) ans += calc(c + x, d);
cout << ans << "\n";
}
}
