#include <bits/stdc++.h>
using namespace std;
long long n, q, s, t, a[200010], node[1000010], l, r, val, tmpl, tmpr, tnpl, tnpr, ans, tmp, tnp;
void update(int id, int x, int y) {
if ((r < x) || (y < l)) return;
if ((l <= x) && (y <= r)) {
node[id] += val;
return;
}
int mid = (x+y)/2;
update(id*2,x,mid);
update(id*2+1,mid+1,y);
}
long long find(int id, int x, int y, int pos) {
if (x == y) return a[x]+node[id];
int mid = (x+y)/2;
node[id*2] += node[id];
node[id*2+1] += node[id];
node[id] = 0;
if (pos <= mid) return find(id*2,x,mid,pos);
else return find(id*2+1,mid+1,y,pos);
}
int main() {
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) {
cin >> a[i];
if (i > 0) {
if (a[i] > a[i-1]) ans += s*(a[i-1]-a[i]);
else ans += t*(a[i-1]-a[i]);
}
}
while (q--) {
cin >> l >> r >> val;
if (r == n) tmpr = 0;
else {
tmp = find(1,0,n,r);
tnp = find(1,0,n,r+1);
if (tmp > tnp) tmpr = (tmp-tnp)*t;
else tmpr = (tmp-tnp)*s;
}
tmp = find(1,0,n,l);
tnp = find(1,0,n,l-1);
if (tmp > tnp) tmpl = (tnp-tmp)*s;
else tmpl = (tnp-tmp)*t;
update(1,0,n);
if (r == n) tnpr = 0;
else {
tmp = find(1,0,n,r);
tnp = find(1,0,n,r+1);
if (tmp > tnp) tnpr = (tmp-tnp)*t;
else tnpr = (tmp-tnp)*s;
}
tmp = find(1,0,n,l);
tnp = find(1,0,n,l-1);
if (tmp > tnp) tnpl = (tnp-tmp)*s;
else tnpl = (tnp-tmp)*t;
ans += (tnpl-tmpl)+(tnpr-tmpr);
cout << ans << endl;
}
}
