#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 2 * 1e5 + 100, M = 4096 + 10, len = 21, inf = 1e18;
const ll mod = 1e9 + 7;
ll a[N], fen[N], s, t;
pll was[N];
void upd(ll i, ll delta){
for(; i < N; i = (i | (i + 1))){
fen[i] += delta;
}
}
ll get(ll r){
ll res = 0;
for(; r >= 0; r = (r & (r + 1)) - 1){
res += fen[r];
}
return res;
}
ll calc(ll a, ll b){
if(a > b) return -(a - b) * s;
else return (b - a) * t;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
ll n, q, ans;
cin >> n >> q >> s >> t;
for(ll i = 0; i <= n; i++){
cin >> a[i];
}
for(ll i = 1; i <= n; i++){
ans += calc(a[i], a[i - 1]);
was[i] = {a[i], a[i - 1]};
upd(i, a[i]);
upd(i + 1, -a[i]);
}
for(ll i = 0, l, r, x; i < q; i++){
cin >> l >> r >> x;
upd(l, x);
upd(r + 1, -x);
ans -= calc(was[l].F, was[l].S);
ll fir = get(l - 1), sec = get(l);
was[l] = {sec, fir};
ans += calc(was[l].F, was[l].S);
if(r + 1 <= n){
ans -= calc(was[r + 1].F, was[r + 1].S);
fir = get(r);
sec = get(r + 1);
was[r + 1] = {sec, fir};
ans += calc(was[r + 1].F, was[r + 1].S);
}
if(i == q - 1) cout << ans << endl;
else cout << ans;
}
return 0;
}
