#include <bits/stdc++.h>
using namespace std;
#define int long long
int N, Q, S, T;
int a[200005], fw[2][200005];
void update(int x, int v, int fwn) { //v is value, x is position
for (;x <=N; x+=x&(-x)) fw[fwn][x] += v;
}
int sum(int x, int fwn) {
int res = 0;
for(; x; x-=x&(-x)) res += fw[fwn][x];
return res;
}
int rs(int x, int y, int fwn) {
return sum(y, fwn) - sum(x-1, fwn);
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> N >> Q >> S >> T;
for (int i = 0; i <= N; i++) {
cin >> a[i];
}
for (int i = N; i > 0; i--) {
a[i] -= a[i-1];
if (a[i] > 0) {
update(i, a[i], 0);
} else if (a[i] < 0) {
update(i, a[i], 1);
}
}
while (Q--) {
int l, r, x;
cin >> l >> r >> x;
r++;
int nl = a[l] + x;
if (nl > 0) {
if (a[l] > 0) {
update(l, x, 0);
} else {
update(l, -1 * a[l], 1);
update(l, nl, 0);
}
} else {
if (a[l] < 0) {
update(l, x, 1);
} else {
update(l, -1 * a[l], 0);
update(l, nl, 1);
}
}
//~ printf("At pos %d, %d updated to %d\n", l, a[l], nl);
a[l] = nl;
x *= -1;
if (r > N) {
int ret = (sum(N, 1) * T * -1) - (sum(N, 0) * S);
cout << ret << '\n';
continue;
}
int nr = a[r] + x;
if (nr > 0) {
if (a[r] > 0) {
update(r, x, 0);
} else {
update(r, -1 * a[r], 1);
update(r, nr, 0);
}
} else {
if (a[r] < 0) {
update(r, x, 1);
} else {
update(r, -1 * a[r], 0);
update(r, nr, 1);
}
}
//~ printf("At pos %d, %d updated to %d\n", r, a[r], nr);
a[r] = nr;
//~ printf("Total incs: %d, Total decs: %d\nList: ", sum(N, 0), sum(N, 1));
//~ int cur = 0;
//~ for (int i = 1; i <= N; i++) {
//~ cout << cur + a[i] << ' ';
//~ cur += a[i];
//~ }
//~ cout << '\n';
int ret = (sum(N, 1) * T * -1) - (sum(N, 0) * S);
cout << ret << '\n';
}
}
