#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<ll, ll>;
using piii = pair<ll, pii>;
#define fi first
#define se second
#define pb push_back
const ll INF = 1e9, mod = 1e9+7, mxn = 2e5+99;
ll N, M, K, S, T;
ll a[mxn], bit[mxn];
void upd(ll x, ll y){
for(; x<mxn; x+=x&(-x)) bit[x] += y;
}
ll que(ll x){
ll res = 0;
for(; x>0; x-=x&(-x))res+=bit[x];
return res;
}
void solve(){
cin >> N >> M >> S >> T;
for(int i=0; i<=N; i++)cin >> a[i];
ll ans = 0;
for(int i=1; i<=N; i++){
if(a[i-1]-a[i] < 0){
ans -= (a[i]-a[i-1])*S;
}else {
ans += (a[i-1]-a[i])*T;
}
}
while(M--){
ll l, r, x;
cin >> l >> r >> x;
ll l1 = que(l), l2 = que(l-1);
if(a[l-1]+l2 - (a[l]+l1) < 0)ans += S * (a[l]+l1 -(a[l-1]+l2));
else ans -= T * (a[l-1]+l2 - (a[l]+l1));
if(r != N){
ll r1 = que(r), r2 = que(r+1);
if((a[r]+r1) - (a[r+1]+r2)< 0)ans += S * ((a[r+1]+r2) - (a[r]+r1));
else ans -= T * ((a[r]+r1) - (a[r+1]+r2));
}
upd(l, x); upd(r+1, -x);
l1 = que(l), l2 = que(l-1);
if(a[l-1]+l2 - (a[l]+l1) < 0)ans -= S * (a[l]+l1 -(a[l-1]+l2));
else ans += T * (a[l-1]+l2 - (a[l]+l1));
if(r != N){
ll r1 = que(r), r2 = que(r+1);
if((a[r]+r1) - (a[r+1]+r2)< 0)ans -= S * ((a[r+1]+r2) - (a[r]+r1));
else ans += T * ((a[r]+r1) - (a[r+1]+r2));
}
cout << ans << "\n";
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
// int tc; cin >> tc; while(tc--)
solve();
return 0;
}
