#include <bits/stdc++.h>
using namespace std;
const int N=200020;
int n,q,s,t;
long long a[N],ret=0;
int main() {
    freopen("foehn.in","r",stdin);
    freopen("foehn.out","w",stdout);
    scanf("%d%d%d%d",&n,&q,&s,&t);
    for (int i=0;i<=n;i++)
    {
        scanf("%lld",&a[i]);
    }
    while (q--)
    {
        int l,r,dis;
        ret=0;
        scanf("%d%d%d",&l,&r,&dis);
        for (int i=l;i<=r;i++)
        {
            a[i]+=dis;
        }
        for (int i=1;i<=n;i++)
        {
            if (a[i]<a[i-1])
            {
                ret+=(a[i-1]-a[i])*t;
            }
            if (a[i]>a[i-1])
            {
                ret-=(a[i]-a[i-1])*s;
            }
        }
        printf("%lld\n",ret);
    } 
}