#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
//Dijkstra->set
//set.find_by_order(x) x-position value
//set.order_of_key(x) number of strictly less elements don't need *set.??
#define N 200005
#define wr cout << "Continue debugging\n";
#define all(x) (x).begin(), (x).end()
#define ll long long int
#define pii pair <int, int>
#define pb push_back
#define ff first
#define ss second
const ll inf = 1e18;
ll t[4*N], lazy[4*N], a[N];
void F(int l, int r, int idx){
if (lazy[idx]){
t[idx] += (r-l+1)*lazy[idx];
if (l != r){
lazy[idx*2] += lazy[idx];
lazy[idx*2+1] += lazy[idx];
}
lazy[idx] = 0;
}
}
void upd(int u, int v, int x, int l, int r, int idx){
F(l, r, idx);
if (l > v or r < u) return;
if (u <= l and r <= v){
t[idx] += (r-l+1)*x;
if (l != r){
lazy[idx*2] += x;
lazy[idx*2+1] += x;
}
return;
}
int md = (l+r)/2;
upd(u, v, x, l, md, idx*2);
upd(u, v, x, md+1, r, idx*2+1);
}
ll find(int pos, int l, int r, int idx){
F(l, r, idx);
if (l == r) return t[idx];
int md = (l+r)/2;
if (pos <= md) return find(pos, l, md, idx*2);
return find(pos, md+1, r, idx*2+1);
}
void build(int l, int r, int idx){
if (l == r){
t[idx] = a[l];
return;
}
int md = (l+r)/2;
build(l, md, idx*2);
build(md+1, r, idx*2+1);
t[idx] = t[idx*2]+t[idx*2+1];
}
int main ()
{
ios::sync_with_stdio(false);
cin.tie(0);
int n, q, s, t;
ll ans = 0;
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++){
cin >> a[i];
if (i and a[i] > a[i - 1]) ans -= s*(a[i]-a[i-1]);
else if (i and a[i] <= a[i - 1]) ans += t*(a[i-1]-a[i]);
}
build(1, n, 1);
while(q--){
int l, r, x;
cin >> l >> r >> x;
ll a2 = find(l, 1, n, 1), a1 = (l == 1 ? 0 : find(l-1, 1, n, 1));
ll b1 = find(r, 1, n, 1), b2 = (r == n ? inf : find(r+1, 1, n, 1));
ans -= (a1 < a2 ? -s : t)*abs(a1-a2);
if (b2 != inf) ans -= (b1 < b2 ? -s : t)*abs(b1-b2);
upd(l, r, x, 1, n, 1);
a2 = find(l, 1, n, 1);
a1 = (l == 1 ? 0 : find(l-1, 1, n, 1));
b1 = find(r, 1, n, 1);
b2 = (r == n ? inf : find(r+1, 1, n, 1));
ans += (a1 < a2 ? -s : t)*abs(a1-a2);
if (b2 != inf) ans += (b1 < b2 ? -s : t)*abs(b1-b2);
// cout << a1 << " " << a2 << " " << b1 << " " << b2 << " " << ans << '\n';
assert(ans <= 1e18);
cout << ans << '\n';
}
}
