#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl "\n"
#define all(x) (x).begin(), (x).end()
using namespace std;
const int INF = (int) 1e9;
const int mod = (int) 1e9+7;
const int MAXN = (int) 3e5+5;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
struct FenwickTreeOneBasedIndexing {
vector<ll> bit; // binary indexed tree
ll n;
FenwickTreeOneBasedIndexing(ll n) {
this->n = n + 1;
bit.assign(n + 1, 0);
}
FenwickTreeOneBasedIndexing(vector<ll> a)
: FenwickTreeOneBasedIndexing(a.size()) {
for (size_t i = 0; i < a.size(); i++)
range_add(i,i, a[i]);
}
ll sum(ll idx) {
ll ret = 0;
for (++idx; idx > 0; idx -= idx & -idx)
ret += bit[idx];
return ret;
}
ll sum(ll l, ll r) {
return sum(r) - sum(l - 1);
}
void add(ll idx, ll delta) {
for (++idx; idx < n; idx += idx & -idx)
bit[idx] += delta;
}
void range_add(ll l, ll r, ll val) {
add(l, val);
add(r + 1, -val);
}
ll point_query(ll idx) {
ll ret = 0;
for (++idx; idx > 0; idx -= idx & -idx)
ret += bit[idx];
return ret;
}
};
ll n,q,s,t;
ll calc(ll a, ll b){
if(a < b){
return -(s*(b-a));
}
else{
return t*(a-b);
}
}
void solve(){
cin >> n >> q >> s >> t;
vector<ll> a(n+1);
for(ll i=0;i<=n;i++){
cin >> a[i];
}
ll ans = 0;
for(int i=0;i<n;i++){
ans += calc(a[i],a[i+1]);
}
FenwickTreeOneBasedIndexing bt(a);
//cout << ans << endl;
while(q--){
ll l,r,val;
cin >> l >> r >> val;
ll nowl = bt.point_query(l);
ll nowr = bt.point_query(r);
ll nowll = bt.point_query(l-1);
ll nowrr = bt.point_query(min(n,r+1));
ll now_suml = calc(nowll,nowl);
ll now_sumr = calc(nowr,nowrr);
bt.range_add(l,r,val);
ll posl = bt.point_query(l);
ll posr = bt.point_query(r);
ll posll = bt.point_query(l-1);
//cout << posll << " " << posl << endl;
ans += calc(posll,posl) - now_suml;
//cout << ans << endl;
if(r!=n){
ll posrr = bt.point_query(r+1);
//cout << posr << " " << posrr << endl;
ans += calc(posr,posrr) - now_sumr;
}
cout << ans << endl;
//break;
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
#ifdef Local
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t=1;
//cin>>t;
while(t--){
solve();
}
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
