#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define maxn 200005
#define f first
#define s second
#define ll long long
#define pb(x) push_back(x)
#define mp make_pair
#define all(x) x.begin(), x.end()
void solve(){
int n, q;
long long s, t;
cin >> n >> q >> s >> t;
long long a[n+1], b[n], sum=0;
cin >> a[0];
for(int i=1; i<=n; i++){
cin >> a[i];
b[i-1]=a[i]-a[i-1];
sum-=max(b[i-1], 0ll)*s+min(b[i-1], 0ll)*t;
}
for(int i=0; i<q; i++){
int l, r, x;
cin >> l >> r >> x;
if(l!=0){
l--;
sum+=max(b[l], 0ll)*s+min(b[l], 0ll)*t;
b[l]+=x;
sum-=max(b[l], 0ll)*s+min(b[l], 0ll)*t;
}if(r!=n){
sum+=max(b[r], 0ll)*s+min(b[r], 0ll)*t;
b[r]-=x;
sum-=max(b[r], 0ll)*s+min(b[r], 0ll)*t;
}
cout << sum << "\n";
}
}
int main(){
cin.tie(nullptr)->sync_with_stdio(0);
int t=1;
//cin >> t;
while(t--){
solve();
cout << "\n";
}
return 0;
}
