#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
#define all(x) x.begin(), x.end()
#define rep(i,a,b) for(int i = a; i < b; i++)
ll fenGet(vll& arr, ll i) {
ll sum = 0;
for(i++; i > 0; i -= i&-i)
sum += arr[i];
return sum;
}
void fenAdd(vll& arr, ll i, ll a) {
for(i++; i < (int)arr.size(); i += i&-i)
arr[i] += a;
}
int main() {
ll N, Q, S, T;
cin >> N;
cin >> Q;
cin >> S;
cin >> T;
vll fenT((N+2)*2);
vll Ad(N+2);
ll last = 0;
rep(n,0,N+1) {
ll a;
cin >> a;
Ad[n] = a-last;
last = a;
}
rep(n,1,N+1) {
ll diff = Ad[n];
fenAdd(fenT, n, diff > 0 ? -diff*S : -diff*T);
}
rep(q,0,Q) {
ll L, R, X;
cin >> L;
cin >> R;
cin >> X;
ll diff = Ad[L];
ll one = diff > 0 ? diff*S : diff*T;
diff = Ad[R+1];
ll two = diff > 0 ? diff*S : diff*T;
Ad[L] += X;
Ad[R+1] -= X;
diff = Ad[L];
fenAdd(fenT, L, one + (diff > 0 ? -diff*S : -diff*T));
diff = Ad[R+1];
fenAdd(fenT, R+1, two + (diff > 0 ? -diff*S : -diff*T));
cout << fenGet(fenT, N) << '\n';
}
}
