#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
#define pll pair<ll,ll>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl;
#define MP make_pair
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define ALL(x) x.begin(),x.end()
#define endl "\n"
const ll maxn=222222;
ll a[maxn],diff[maxn];
ll n,q,s,t;
ll f(ll x){
if(x>0)return -x*s;
else return -x*t;
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin>>n>>q>>s>>t;
rep(i,0,n+1)cin>>a[i];
ll ans=0;
rep(i,1,n+1){
diff[i]=a[i]-a[i-1];
//debug(f(diff[i]));
ans+=f(diff[i]);
}
//debug(ans);
while(q--){
ll l,r,val;
cin>>l>>r>>val;
ans-=f(diff[l]);
diff[l]+=val;
ans+=f(diff[l]);
if(r!=n){
ans-=f(diff[r+1]);
diff[r+1]-=val;
ans+=f(diff[r+1]);
}
cout<<ans<<endl;
}
return 0;
}
