#include<bits/stdc++.h>
const char nl = '\n';
using namespace std;
using ll = long long;
ll s, t;
struct Segtree {
struct node {
ll le, ri, wd; // leftest element, rightest element, power of wind
};
vector<ll> tree;
vector<ll> sh;
vector<ll> a;
ll sz = 1;
ll nope = 0;
void init(ll n) {
while (sz < n) {
sz *= 2;
}
tree.assign(2*sz+1, 0);
sh.assign(2*sz+1, 0);
a.assign(n+10, 0);
}
void create(ll n) {
for (ll i = 0, lf = sz-1; i <= n; i ++, lf ++) {
tree[lf] = a[i];
}
}
void build(ll x, ll lx, ll rx) {
if (rx - lx == 1) {
return ;
}
ll mid = (lx + rx) / 2;
build(2*x+1, lx, mid);
build(2*x+2, mid, rx);
tree[x] = tree[2*x+1] + tree[2*x+2];
}
void build() {
build(0, 0, sz);
}
void push(ll x, ll lx, ll rx) {
if (sh[x] == nope) return ;
if (rx - lx == 1) return ;
sh[2*x+1] += sh[x];
tree[2*x+1] += sh[x];
sh[2*x+2] += sh[x];
tree[2*x+2] += sh[x];
sh[x] = nope;
}
void update(ll l, ll r, ll v, ll x, ll lx, ll rx) {
push(x, lx, rx);
if (lx >= r || rx <= l) {
return ;
}
if (l <= lx && rx <= r) {
sh[x] += v;
push(x, lx, rx);
tree[x] += v;
return ;
}
ll mid = (lx + rx) / 2;
update(l, r, v, 2*x+1, lx, mid);
update(l, r, v, 2*x+2, mid, rx);
tree[x] = tree[2*x+1] + tree[2*x+2];
}
void update(ll l, ll r, ll v) {
update(l, r, v, 0, 0, sz);
}
ll get(ll i, ll x, ll lx, ll rx) {
push(x, lx, rx);
if (rx - lx == 1) {
return tree[x];
}
ll mid = (lx + rx) / 2;
if (i < mid) {
return get(i, 2*x+1, lx, mid);
} else {
return get(i, 2*x+2, mid, rx);
}
}
ll get(ll i) {
return get(i, 0, 0, sz);
}
void debug() {
for (ll i = 0; i < 2*sz-1; i ++) {
cout << i << ": " << tree[i] << nl;
}
}
};
ll wind(ll x, ll y) {
return (x < y ? s * (x - y) : t * (x - y));
}
void solve() {
ll n, q;
cin >> n >> q >> s >> t;
Segtree sg;
n ++;
sg.init(n);
for (ll i = 0; i < n; i ++) {
cin >> sg.a[i];
}
sg.create(n);
sg.build();
ll res = 0;
for (ll i = 0; i < n-1; i ++) {
res += wind(sg.a[i], sg.a[i+1]);
}
for (ll i = 0; i < q; i ++) {
ll l, r, v;
cin >> l >> r >> v;
r ++;
res -= wind(sg.get(l-1), sg.get(l));
if (r != n) {
res -= wind(sg.get(r-1), sg.get(r));
}
sg.update(l, r, v);
res += wind(sg.get(l-1), sg.get(l));
if (r != n) {
res += wind(sg.get(r-1), sg.get(r));
}
cout << res << nl;
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
ll tst = 1;
// cin >> tst;
while (tst --) {
solve();
cout << nl;
}
}
