#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int n, q, s, t;
int a[1000005], diff[1000005];
ll val(ll x) {
if(x > 0) return -x*s;
return -x*t;
}
int l, r, x;
int main() {
cin.tie(0) -> sync_with_stdio(0);
cin >> n >> q >> s >> t;
for(int i=0;i<=n;i++) {
cin >> a[i];
}
ll csum = 0;
for(int i=1;i<=n;i++) {
diff[i] = a[i] - a[i-1];
csum += val(diff[i]);
//cout << csum << '\n';
}
//cout << csum << '\n';
while(q--) {
cin >> l >> r >> x;
csum -= val(diff[l]);
diff[l] += x;
csum += val(diff[l]);
r++;
if(r<=n){
csum -= val(diff[r]);
diff[r] -= x;
csum += val(diff[r]);
}
cout << csum << '\n';
}
}
