#include <iostream>
using namespace std;
#define ll long long
const int N = 2e5 + 10;
int n, m;
ll A, B, a[N];
ll low, high;
struct SEG {
ll val[N << 2];
void build(int l, int r, int id) {
if (l == r) {
val[id] = a[l];
return;
}
int mid = (l + r) >> 1;
build(l, mid, id << 1);
build(mid + 1, r, id << 1 | 1);
val[id] = 0;
}
void down(int id) {
if (!val[id]) return;
val[id << 1] += val[id];
val[id << 1 | 1] += val[id];
val[id] = 0;
}
void update(int l, int r, int u, int v, ll VAL, int id) {
if (l > v || r < u) return;
if (l >= u && r <= v) {
val[id] += VAL;
return;
}
int mid = (l + r) >> 1;
down(id);
update(l, mid, u, v, VAL, id << 1);
update(mid + 1, r, u, v, VAL, id << 1 | 1);
}
ll get(int l, int r, int u, int id) {
if (u == 0) return 0;
if (l == r) return val[id];
int mid = (l + r) >> 1;
down(id);
if (u <= mid) return get(l, mid, u, id << 1);
return get(mid + 1, r, u, id << 1 | 1);
}
} seg;
int main() {
cin.tie(0); cout.tie(0);
ios_base::sync_with_stdio(false);
cin >> n >> m >> A >> B;
for (int i = 0; i <= n; ++i) {
cin >> a[i];
if (a[i] > a[i - 1]) {
high += a[i] - a[i - 1];
} else {
low += a[i - 1] - a[i];
}
}
seg.build(1, n, 1);
int l, r;
ll w;
while (m--) {
cin >> l >> r >> w;
ll curL = seg.get(1, n, l, 1), bL = seg.get(1, n, l - 1, 1);
if (curL > bL) {
high -= (curL - bL);
} else {
low -= (bL - curL);
}
ll curR, aR;
if (r != n) {
curR = seg.get(1, n, r, 1), aR = seg.get(1, n, r + 1, 1);
if (aR > curR) {
high -= (aR - curR);
} else {
low -= (curR - aR);
}
}
seg.update(1, n, l, r, w, 1);
curL += w;
if (curL > bL) {
high += (curL - bL);
} else {
low += (bL - curL);
}
if (r != n) {
curR += w;
if (aR > curR) {
high += (aR - curR);
} else {
low += (curR - aR);
}
}
cout << low * B - high * A << "\n";
}
return 0;
}
