#include <bits/stdc++.h>
#define pb push_back
#define ll long long
#define vll vector<ll>
#define vbool vector<bool>
#define pairll pair<ll,ll>
#define fi first
#define sc second
#define rever greater<ll>()
using namespace std;
void solve(){
ll n, q, s, t; cin >> n >> q >> s >> t;
vll a(n+1); for(ll i = 0; i <= n; i++) cin >> a[i];
ll res = 0; vll b(n+1);
for(ll i = 1; i <= n; i++){
b[i] = a[i]-a[i-1];
if(b[i]>0){
res -= b[i]*s;
}else res += abs(b[i])*t;
}
ll l, r, x;
while(q--){
// for(ll i = 1; i <= n; i++){
// cout << b[i] << ' ';
// }cout << endl;
// cout << '>';
// cout << res << endl;
cin >> l >> r >> x;
if(b[l]>0){
res += b[l]*s;
}else res -= abs(b[l])*t;
b[l]+=x;
if(b[l]>0){
res -= b[l]*s;
}else res += abs(b[l])*t;
r++;
if(r == n+1){
cout << res << endl; continue;
}
if(b[r]>0){
res += b[r]*s;
}else res -= abs(b[r])*t;
b[r]-=x;
if(b[r]>0){
res -= b[r]*s;
}else res += abs(b[r])*t;
cout << res << endl;
}
}
int main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
ll t=1; //cin >> t;
for(int i = 1; i <= t; i++){
solve();
}
}
