#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll mxn = 2e5+10;
int main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
ll n,q;
cin>>n>>q;
ll S,T;
cin>>S>>T;
ll arr[n+1];
ll ans = 0;
for(int i = 0;i<=n;i++)cin>>arr[i];
for(int i = 1;i<=n;i++){
if(arr[i]>arr[i-1])ans -= S*(arr[i]-arr[i-1]);
else ans += T*(arr[i-1]-arr[i]);
}
for(int i = n;i>=1;i--){
arr[i] = arr[i]-arr[i-1];
}
while(q--){
ll l,r,k;
cin>>l>>r>>k;
if(arr[l]<0)ans -= abs(arr[l])*T;
else ans += abs(arr[l])*S;
arr[l] += k;
if(arr[l]<0)ans += abs(arr[l])*T;
else ans -= abs(arr[l])*S;
l = r+1;
if(l>n){
cout<<ans<<'\n';
continue;
}
if(arr[l]<0)ans -= abs(arr[l])*T;
else ans += abs(arr[l])*S;
arr[l] -= k;
if(arr[l]<0)ans += abs(arr[l])*T;
else ans -= abs(arr[l])*S;
cout<<ans<<'\n';
}
return 0;
}
