# include <bits/stdc++.h>
# define int long long
# define vi vector<int>
# define pb push_back
# define pii pair<int, int>
# define fi first
# define se second
# define endl '\n'
# define jess ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
int n, q, s, t, a[200005], dif[200005];
void solve() {
cin >> n >> q >> s >> t;
int pos=0, neg=0;
for(int i=0; i<=n; i++) {
cin >> a[i];
if(i>=1) {
dif[i]=a[i]-a[i-1];
if(dif[i]<=0) neg+=dif[i];
if(dif[i]>0) pos+=dif[i];
}
}
for(int i=1; i<=q; i++) {
// cout << "idx " << i << endl;
// cout << "bef " << pos << " " << neg << endl;
int l, r, x;
cin >> l >> r >> x;
if(dif[l]+x>0) {
if(dif[l]<=0) {
neg-=dif[l];
} else {
pos-=dif[l];
}
dif[l]+=x;
pos+=dif[l];
} else {
if(dif[l]<=0) neg-=dif[l];
else pos-=dif[l];
dif[l]+=x;
neg+=dif[l];
}
r++;
if((dif[r]-x>0) && (r<=n)) {
if(dif[r]<=0) {
neg-=dif[r];
} else {
pos-=dif[r];
}
dif[r]-=x;
pos+=dif[r];
} else if (r<=n){
if(dif[r]<=0) neg-=dif[r];
else pos-=dif[r];
dif[r]-=x;
neg+=dif[r];
}
// cout << "aft " << pos << " " << neg << endl;
cout << (-1)*neg*t - pos*s << endl;
}
}
signed main() {
jess;
solve();
}
