#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pi;
typedef vector <ll> vi;
typedef vector <pi> vpi;
#define f first
#define s second
#define FOR(i,s,e) for(ll i=s;i<=ll(e);++i)
#define DEC(i,s,e) for(ll i=s;i>=ll(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0)
#define maxn 200101
#define int ll
int N,Q,S,T;
int fw[maxn],A[maxn];
void update(int p,int v){ //update position p by +=v
for (int i=p; i<=N+10; i+= (i&(-i))){
fw[i] += v;
}
}
void upd(int a,int b, int c){ //update position a to b by +=c
update(a,c); //upd function from the PURQ fenwick
update(b+1,-c);
}
int qry(int p){ //query p
int ans = 0;
for (int i = p; i>0; i -= (i&(-i))){
ans += fw[i];
}
return ans;
}
int32_t main(){
fast;
cin>>N>>Q>>S>>T;
FOR(i,0,N){
cin>>A[i]; if (i != 0) upd(i,i,A[i]);
}
int cur = 0;
FOR(i,0,N-1){
if (A[i] < A[i+1]) cur -= S * (A[i+1] - A[i]);
else cur += T * (A[i] - A[i+1]);
}
FOR(i,1,Q){
int a,b,c;
cin>>a>>b>>c;
int Aval = qry(a);
int Aprev = qry(a-1);
int Bval = qry(b);
if (Aprev < Aval) cur += S * (Aval - Aprev);
else cur -= T * (Aprev - Aval);
Aval += c;
if (Aprev < Aval) cur -= S * (Aval - Aprev);
else cur += T * (Aprev - Aval);
if (b+1 <= N){
int Bnext = qry(b+1);
if (Bval < Bnext) cur += S * (Bnext - Bval);
else cur -= T * (Bval - Bnext);
Bval += c;
if (Bval < Bnext) cur -= S * (Bnext - Bval);
else cur += T * (Bval - Bnext);
}
cout<<cur<<'\n';
upd(a,b,c);
}
}
