#include<bits/stdc++.h>
using namespace std;
long long n,q,s,t,a[200005],sum;
int main(){
    freopen("foehn.in","r",stdin);
    freopen("foehn.out","w",stdout);
    scanf("%lld%lld%lld%lld",&n,&q,&s,&t);
    for (long long i=0;i<=n;i++){
        scanf("%lld",&a[i]);
    }
    for (long long i=1;i<=q;i++){
        long long l,r,x;
        scanf("%lld%lld%lld",&l,&r,&x);
        sum=0;
        for (long long j=0;j<=n;j++){
            if (l<=j&&r>=j){
                a[j]+=x;
            }
            if (j!=0){
                if (a[j]>a[j-1]){
                    sum-=s*(a[j]-a[j-1]);
                }else{
                    sum+=t*(a[j-1]-a[j]);
                }
            }
        }
        printf("%lld\n",sum);
    }
    return 0;
}