#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=2e5+7;
ll tr[4*LIM], N=1;
void upd(int l, int r, ll x) {
l+=N; r+=N;
tr[l]+=x;
if(l!=r) tr[r]+=x;
while(l/2!=r/2) {
if(l%2==0) tr[l+1]+=x;
if(r%2==1) tr[r-1]+=x;
l/=2; r/=2;
}
}
ll cnt(int v) {
v+=N;
ll ans=0;
while(v) {
ans+=tr[v];
v/=2;
}
return ans;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
ll n, q, s, t, ans=0;
cin >> n >> q >> s >> t;
while(N<=n) N*=2;
rep(i, n+1) {
cin >> tr[N+i];
if(tr[N+i-1]<tr[N+i]) ans-=s*(tr[N+i]-tr[N+i-1]);
else ans+=t*(tr[N+i-1]-tr[N+i]);
}
while(q--) {
int l, r, x;
cin >> l >> r >> x;
if(cnt(l-1)<cnt(l)) ans+=s*(cnt(l)-cnt(l-1));
else ans-=t*(cnt(l-1)-cnt(l));
if(r<n) {
if(cnt(r)<cnt(r+1)) ans+=s*(cnt(r+1)-cnt(r));
else ans-=t*(cnt(r)-cnt(r+1));
}
upd(l, r, x);
if(cnt(l-1)<cnt(l)) ans-=s*(cnt(l)-cnt(l-1));
else ans+=t*(cnt(l-1)-cnt(l));
if(r<n) {
if(cnt(r)<cnt(r+1)) ans-=s*(cnt(r+1)-cnt(r));
else ans+=t*(cnt(r)-cnt(r+1));
}
cout << ans << '\n';
}
}
