//In The Name Of ALLAH!
#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define ld long double
#define endl '\n'
#define pb push_back
#define pf push_front
#define Zemur007 ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define bpc __builtin_popcountll
#define btz __builtin_ctzll
#define all(x) x.begin() , x.end()
#define allr(x) x.rbegin() , x.rend()
#define F first
#define S second
#define pii pair<int , int>
#define pll pair<ll , ll>
#define turtle tuple<ll , ll , ll>
#define pss pair<string , string>
#define YES cout << "YES" << endl;
#define NO cout << "NO" << endl;
#define indexed_set tree<pll , null_type , less<pll> , rb_tree_tag , tree_order_statistics_node_update>
const ll sz = 1e6 + 5 , INF = 1e18 , MOD = 1e9 + 7;
ll a[sz];
struct BIT{
vector<ll> ft;
BIT(ll n){
ft.assign(n + 1 , 0);
}
void update(ll x , ll val){
for(ll i = x ; i <= ft.size() ; i += i & -i) ft[i] += val;
}
ll get(ll x){
ll ans = 0;
for(ll i = x ; i > 0 ; i -= i & -i) ans += ft[i];
return ans;
}
ll query(ll l , ll r){
return get(r) - get(l - 1);
}
};
ll calc(ll x , ll y , ll s , ll t){
if(y > x){
ll diff = y - x;
return -(diff * s);
}
else{
ll diff = x - y;
return diff * t;
}
}
ll mask , i , j , k;
void solve(){
ll n , q , s , t; cin >> n >> q >> s >> t;
ll last = 0;
for(i = 1 ; i <= n + 1 ; i++) cin >> a[i];
for(i = 2 ; i <= n + 1 ; i++){
last += calc(a[i - 1] , a[i] , s , t);
}
BIT ft(n + 3);
for(i = 1 ; i <= q ; i++){
ll l , r , x; cin >> l >> r >> x;
l++; r++;
last -= calc(a[l - 1] + ft.get(l - 1) , a[l] + ft.get(l) , s , t);
if(r + 1 <= n + 1) last -= calc(a[r] + ft.get(r) , a[r + 1] + ft.get(r + 1) , s , t);
ft.update(l , x);
ft.update(min(r + 1 , n + 2) , -x);
last += calc(a[l - 1] + ft.get(l - 1) , a[l] + ft.get(l) , s , t);
if(r + 1 <= n + 1) last += calc(a[r] + ft.get(r) , a[r + 1] + ft.get(r + 1) , s , t);
cout << last << endl;
}
}
/*
3 1 1 2
0
4
1
8
1 2 2
*/
signed main(){
Zemur007;
// open();
#ifdef LOCAL
freopen("output.txt","w",stdout);
#endif
ll t = 1;
// cin >> t;
while(t--){
solve();
}
// for(ll testcase = 1 ; testcase <= t ; testcase++){
// cout << "Case " << testcase << ":" << endl;
// solve();
// }
}
