#include <bits/stdc++.h>
using namespace std;
long long n,q,s,t,a[200010];
int main () {
    freopen("foehn.in","r",stdin);
    freopen("foehn.out","w",stdout);
    cin >> n >> q >> s >> t;
    for (int i=0;i<=n;i++) {
        cin >> a[i];
    }
    while (q--) {
        long long l,r,k,res=0;
        cin >> l >> r >> k;
        for (int i=l;i<=r;i++) {
            a[i]+=k;
        }
        for (int i=0;i<n;i++) {
            if (a[i]<a[i+1]) res-=(a[i+1]-a[i])*s;
            else res+=(a[i]-a[i+1])*t;
        }
        cout << res <<endl;
    }
    return 0;
}