// Make the best become better
// No room for laziness
#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e6 + 5;
const int mod = 1e9 + 7;
const ll oo = 1e18;
int n, q, s, t;
int a[maxN];
int res = 0;
int st[4 * maxN], lazy[4 * maxN];
void down(int id)
{
int t = lazy[id];
lazy[id] = 0;
st[id * 2] += t;
lazy[id * 2] += t;
st[id * 2 + 1] += t;
lazy[id * 2 + 1] += t;
}
void build(int id, int l, int r)
{
if(l == r)
{
st[id] = a[l];
return;
}
int mid = (l + r) / 2;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
}
void update(int id, int l, int r, int u, int v, int val)
{
if(l > v || r < u) return;
if(l >= u && r <= v)
{
st[id] += val;
lazy[id] += val;
return;
}
int mid = (l + r) / 2;
down(id);
update(id * 2, l, mid, u, v, val);
update(id * 2 + 1, mid + 1, r, u, v, val);
}
int get(int id, int l, int r, int pos)
{
if(l == r) return st[id];
int mid = (l + r) / 2;
down(id);
if(pos <= mid) return get(id * 2, l, mid, pos);
return get(id * 2 + 1, mid + 1, r, pos);
}
void ReadInput()
{
cin >> n >> q >> s >> t;
for(int i=0; i<=n; i++)
cin >> a[i];
for(int i=1; i<=n; i++)
{
if(a[i] >= a[i - 1]) res -= (a[i] - a[i - 1]) * s;
else res += (a[i - 1] - a[i]) * t;
}
}
void Solve()
{
build(1, 0, n);
while(q--)
{
int l, r, x;
cin >> l >> r >> x;
int val1 = get(1, 0, n, l), val2 = get(1, 0, n, l - 1);
if(val1 >= val2) res += s * (val1 - val2);
else res -= t * (val2 - val1);
if(r < n)
{
int val1 = get(1, 0, n, r), val2 = get(1, 0, n, r + 1);
if(val2 >= val1) res += s * (val2 - val1);
else res -= t * (val1 - val2);
}
update(1, 0, n, l, r, x);
val1 = get(1, 0, n, l), val2 = get(1, 0, n, l - 1);
if(val1 >= val2) res -= s * (val1 - val2);
else res += t * (val2 - val1);
if(r < n)
{
int val1 = get(1, 0, n, r), val2 = get(1, 0, n, r + 1);
if(val2 >= val1) res -= s * (val2 - val1);
else res += t * (val1 - val2);
}
cout << res << '\n';
}
}
int32_t main()
{
// freopen("sol.inp", "r", stdin);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
ReadInput();
Solve();
}
