#include <bits/stdc++.h>
using namespace std;
using ll = long long;
vector<int> a;
vector<ll> st, lz;
ll bld(int nd, int l, int r) {
if (l == r) {
return st[nd] = a[l];
}
int ch = nd<<1, md = (l + r)>>1;
return st[nd] = bld(ch, l, md) + bld(ch + 1, md + 1, r);
}
void LZ(int nd, int l, int r) {
st[nd] += (r - l + 1) * lz[nd];
if (l != r) {
int ch = nd<<1;
lz[ch] += lz[nd];
lz[ch + 1] += lz[nd];
}
lz[nd] = 0;
}
void upd(int nd, int l, int r, int x, int y, int val) {
LZ(nd, l, r);
if (r < x || y < l) return;
if (x <= l && r <= y) {
lz[nd] += val;
}
else {
int ch = nd<<1, md = (l + r)>>1;
upd(ch, l, md, x, y, val);
upd(ch + 1, md + 1, r, x, y, val);
}
}
ll fnd(int nd, int l, int r, int x) {
LZ(nd, l, r);
if (l > x || x > r) return 0;
if (l == r) return st[nd];
int ch = nd<<1, md = (l + r)>>1;
return fnd(ch, l, md, x) + fnd(ch + 1, md + 1, r, x);
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n, q, s, t;
cin >> n >> q >> s >> t;
a.assign(n + 1, 0);
st.assign((n<<2) + 5, 0);
lz.assign((n<<2) + 5, 0);
ll ans = 0;
for (int i = 0; i <= n; i++) {
cin >> a[i];
if (i) ans += 1LL * (a[i - 1] < a[i] ? s : t) * (a[i - 1] - a[i]);
}
bld(1, 0, n);
while (q--) {
int l, r, x;
cin >> l >> r >> x;
if (l) {
ll y = fnd(1, 0, n, l - 1), z = fnd(1, 0, n, l);
ans -= 1LL * (y < z ? s : t) * (y - z);
}
if (r != n) {
ll y = fnd(1, 0, n, r), z = fnd(1, 0, n, r + 1);
ans -= 1LL * (y < z ? s : t) * (y - z);
}
upd(1, 0, n, l, r, x);
if (l) {
ll y = fnd(1, 0, n, l - 1), z = fnd(1, 0, n, l);
ans += 1LL * (y < z ? s : t) * (y - z);
}
if (r != n) {
ll y = fnd(1, 0, n, r), z = fnd(1, 0, n, r + 1);
ans += 1LL * (y < z ? s : t) * (y - z);
}
cout << ans << '\n';
}
}
