//Huyduocdithitp
#include<bits/stdc++.h>
typedef long long ll;
#define endl '\n'
#define fi first
#define se second
#define pii pair<ll,ll>
#define N 400005
#define LOG 18
using namespace std;
const ll inf = 1e8, base = 311, mod = 1e9 + 7;
bool ghuy4g;
ll n, q, S, T, sum = 0, a[N], st[4 * N], f[4 * N];
void build(ll id, ll l, ll r) {
if (l == r) {
st[id] = a[l];
return;
}
ll mid = (l + r) / 2;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
}
void lazy(ll id) {
if (f[id] == 0) return;
st[id] += f[id];
f[id * 2] += f[id];
f[id * 2 + 1] += f[id];
f[id] = 0;
}
void update(ll id, ll l, ll r, ll L, ll R, ll v) {
lazy(id);
if (l > R || r < L) {
return;
}
if (L <= l && r <= R) {
f[id] += v;
lazy(id);
return;
}
ll mid = (l + r) / 2;
update(id * 2, l, mid, L, R, v);
update(id * 2 + 1, mid + 1, r, L, R, v);
}
ll get(ll id, ll l, ll r, ll i) {
if (i < 0 || i > n) return 0;
lazy(id);
if (i > r || i < l) return 0;
if (l == r) {
return st[id];
}
ll mid = (l + r) / 2;
return get(id * 2, l, mid, i) + get(id * 2 + 1, mid + 1, r, i);
}
bool klinh;
signed main() {
//freopen("boardgame.inp", "r", stdin);
//freopen("boardgame.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> q >> S >> T;
for (int i = 0; i <= n; i ++) {
cin >> a[i];
if (a[i - 1] < a[i]) {
sum += S * (a[i] - a[i - 1]);
}
else if (a[i - 1] >= a[i]){
sum += T * (a[i] - a[i - 1]); // tang
}
}
build(1, 1, n);
for (int i = 1; i <= q; i ++) {
ll l, r, x;
cin >> l >> r >> x;
if (1) {
ll old_l = get(1, 1, n, l);
ll prev = get(1, 1, n, l - 1);
if (prev < old_l) {
sum -= S * (old_l - prev);
}
else {
sum -= T * (old_l - prev);
}
}
if (r < n) {
ll old_r = get(1, 1, n, r);
ll sau = get(1, 1, n, r + 1);
if (old_r < sau) {
sum -= S * (sau - old_r);
}
else {
sum -= T * (sau - old_r);
}
}
update(1, 1, n, l, r, x);
if (1) {
ll old_l = get(1, 1, n, l);
ll prev = get(1, 1, n, l - 1);
if (prev < old_l) {
sum += S * (old_l - prev);
}
else {
sum += T * (old_l - prev);
}
}
if (r < n) {
ll old_r = get(1, 1, n, r);
ll sau = get(1, 1, n, r + 1);
if (old_r < sau) {
sum += S * (sau - old_r);
}
else {
sum += T * (sau - old_r);
}
}
cout << -sum << endl;
}
cerr << fabs(&klinh - &ghuy4g) / double(1024 * 1024);
return 0;
}
