#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll maxn = 2e5 + 17;
struct fentree {
ll sz;
vector<ll> val;
void init(ll n){
sz = n;
val.assign(sz , 0);
return;
}
void add(ll i , ll k){
ll h = i;
while(h < sz){
val[h] += k;
h |= (h + 1);
}
return;
}
ll cal(ll i){
ll h = i , res = 0;
while(~h){
res += val[h];
h &= (h + 1); h--;
}
return res;
}
};
ll n , q , s , t;
fentree ft;
ll a[maxn];
ll dif(ll a , ll b){
return (b > a ? s : t) * (a - b);
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>q>>s>>t;
for(ll i = 0 ; i <= n ; i++){
cin>>a[i];
}
ft.init(n + 1);
for(ll i = 1 ; i <= n ; i++){
ft.add(i , a[i] - a[i - 1]);
}
ll res = 0;
for(ll i = 1 ; i <= n ; i++){
res += dif(a[i - 1] , a[i]);
}
for(ll e = 0 ; e < q ; e++){
ll l , r , k;
cin>>l>>r>>k;
ll hl = ft.cal(l - 1) , hr = ft.cal(l);
ll pr = dif(hl , hr) , cur = dif(hl , hr + k);
res += cur - pr;
if(r < n){
hl = ft.cal(r); hr = ft.cal(r + 1);
pr = dif(hl , hr); cur = dif(hl + k , hr);
res += cur - pr;
}
ft.add(l , k); ft.add(r + 1 , -k);
cout<<res<<'\n';
}
return 0;
}
