#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define F first
#define S second
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, q;
cin>>n>>q;
ll s, t;
cin>>s>>t;
vector<ll> a(n + 1);
for(auto &i : a) {
cin>>i;
}
vector<ll> d(n + 1);
for(int i=1;i<=n;++i) {
d[i] = a[i] - a[i - 1];
}
auto c = [&](ll f) -> ll {
return f > 0 ? -s * f : -t * f;
};
ll ans = 0;
for(int i=1;i<=n;++i) {
ans += c(d[i]);
}
while(q--) {
int l, r;
ll x;
cin>>l>>r>>x;
ans -= c(d[l]);
d[l] += x;
ans += c(d[l]);
if(r + 1 <= n) {
ans -= c(d[r + 1]);
d[r + 1] -= x;
ans += c(d[r + 1]);
}
cout<<ans<<'\n';
}
return 0;
}
