#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ff first
#define ss second
#define pb push_back
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define N 200005
#define INF 0x3f3f3f3f
#define MOD 1000000007LL
ll a[N];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, q;
ll s, t;
cin>>n>>q>>s>>t;
for(int i = 0; i <= n; i++)
cin>>a[i];
ll T = 0;
for(int i = n; i >= 1; i--){
a[i] -= a[i - 1];
T += (a[i] > 0 ? s : t) * -a[i];
}
while(q--){
int l, r;
ll x;
cin>>l>>r>>x;
++r;
T -= (a[l] > 0 ? s : t) * -a[l];
a[l] += x;
T += (a[l] > 0 ? s : t) * -a[l];
if(r <= n){
T -= (a[r] > 0 ? s : t) * -a[r];
a[r] -= x;
T += (a[r] > 0 ? s : t) * -a[r];
}
cout<<T<<'\n';
}
}
