#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;
int N,Q,S,T;
ll sum;
vl A, dif;
ll calc(int x) {
if (dif[x] > 0) return -S*dif[x];
return -T*dif[x];
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> Q >> S >> T; A.resize(N+1);
F0R(i,N+1) cin >> A[i];
F0R(i,N) {
dif.pb(A[i+1]-A[i]);
sum += calc(i);
}
F0R(i,Q) {
int L,R,X; cin >> L >> R >> X;
if (L) {
sum -= calc(L-1);
dif[L-1] += X;
sum += calc(L-1);
}
if (R < N) {
sum -= calc(R);
dif[R] -= X;
sum += calc(R);
}
cout << sum << "\n";
}
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
