#include <bits/stdc++.h>
#define ll long long
#define pll pair<ll, ll>
#define pii pair<ll, pll>
#define pb push_back
#define fi first
#define se second
using namespace std;
const int N = 5e5 + 5;
const int M = 1300;
const ll mod = 1e15 + 7;
ll n, m, t, k, ans, b[N], dp[N], a[N], d[N], l[N], r[N], lab[N], s, pos, neg;
vector<pll> adj[N];
vector<ll> kq, adt[N];
vector<pii> e;
ll pw(ll k, ll n)
{
ll total = 1;
for(; n; n >>= 1)
{
if(n & 1)total = total * k % mod;
k = k * k % mod;
}
return total;
}
ll findp(ll u)
{
return lab[u] < 0 ? u : lab[u] = findp(lab[u]);
}
void hop(ll u, ll v)
{
if(lab[u] > lab[v])swap(u, v);
lab[u] += lab[v];
lab[v] = u;
}
void add(ll x)
{
if(x > 0)pos += x;
else neg -= x;
}
void del(ll x)
{
if(x > 0)pos -= x;
else neg += x;
}
void sol()
{
cin >> n >> m >> s >> t;
for(int i = 0; i <= n; i ++)
{
cin >> a[i];
b[i] = a[i] - a[i-1];
add(b[i]);
}
while(m -- > 0)
{
ll l, r, x;
cin >> l >> r >> x;
del(b[l]);
b[l] += x;
add(b[l]);
if(r < n)
{
del(b[r+1]);
b[r+1] -= x;
add(b[r+1]);
}
cout << neg*t-pos*s<<'\n';
}
}
int main()
{
cin.tie(0);
cout.tie(0);
ios_base::sync_with_stdio(0);
int test = 1;
//cin >> test;
while (test-- > 0)
sol();
return 0;
}
/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5
*/
// ctrl + F8 = compile
// ctrl + F9 = run
