// #pragma GCC optimize("O3,Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define MP make_pair
#define pb push_back
#define REP(i,n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const double EPS = 0.00001;
const int INF = 1e9+500;
const int N = 3e5+5;
const int ALPH = 26;
const int LGN = 25;
constexpr int MOD = 1e9+7;
int n,q,s,t;
vector<int> d;
int ans = 0;
void upd(int ind, int x) {
if(d[ind] > 0) {
ans += s * d[ind];
}
else {
ans += t * d[ind];
}
d[ind] += x;
if(d[ind] > 0) {
ans -= s * d[ind];
}
else {
ans -= t * d[ind];
}
}
inline void solve() {
cin>>n>>q>>s>>t;
vector<int> a(n + 1);
REP(i, n + 1) cin >> a[i];
d.assign(n + 3, 0);
for(int i = 1; i<=n; i++) {
d[i] = a[i] - a[i - 1];
if(d[i] > 0) {
ans -= s * d[i];
}
else {
ans -= t * d[i];
}
}
REP(z, q) {
int l, r, x;
cin >> l >> r >> x;
if(r + 1 <= n) upd(r + 1, -x);
upd(l, x);
cout << ans << "\n";
}
}
signed main() {
fastio();
int test = 1;
//cin>>test;
while(test--) {
solve();
}
}
