#include <bits/stdc++.h>
#define ll long long
#define dl double
#define str string
#define tst to_string
#define pb push_back
#define pf push_front
#define eb emplace_back
#define u_b upper_bound
#define l_b lower_bound
#define ff first
#define ss second
#define INF 1000000001
#define mxn 100001
#define mod 998244353
#define all(v) v.begin(),v.end()
#define come_on ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
using namespace std;
int main()
{
ll n,q,s,t;
cin>>n>>q>>s>>t;
vector<ll>a(n+1);
for(int i=0;i<=n;i++)
{
cin>>a[i];
}
while(q--)
{
int l,r,x;
cin>>l>>r>>x;
for(int i=l;i<=r;i++)
{
a[i]+=x;
}
ll ans=0;
for(int i=0;i<n;i++)
{
if(a[i]<a[i+1])
{
ans-=(a[i+1]-a[i])*s;
}
else
{
ans+=(a[i]-a[i+1])*t;
}
}
cout<<ans<<'\n';
}
}
//1
