#include <bits/stdc++.h>
#define fi first
#define se second
#define ryan bear
#define all(V) ((V).begin()), ((V).end())
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
typedef vector<int> vim;
typedef vector<ll> vlm;
int N, Q; ll S, T;
ll A[1000010];
int L, R; ll X, now;
struct dt {
ll ar[(1<<22)], lz[(1<<22)];
void init() { for (int i=0; i<=N; i++) upd(i, i, A[i]); }
int get(int t, int s, int e, int ind) {
spread(ind);
if (s==e) return ar[ind];
int md=(s+e)/2;
if (t<=md) return get(t, s, md, ind*2);
else return get(t, md+1, e, ind*2+1);
}
void upd(int is, int ie, int s, int e, int ind, ll val) {
if (s>e) return ;
if (is<=s&&e<=ie) { lz[ind]=val; return ; }
int md=(s+e)/2;
if (is<=md) upd(is, ie, s, md, ind*2, val);
if (md+1<=ie) upd(is, ie, md+1, e, ind*2+1, val);
}
void spread(int i) {
if (i<(1<<21)) lz[i*2]+=lz[i], lz[i*2+1]+=lz[i];
ar[i]+=lz[i]; lz[i]=0;
}
void upd(int is, int ie, ll val) { upd(is, ie, 0, N, 1, val); }
int get(int t) { return get(t, 0, N, 1); }
}DS;
ll f(ll a, ll b) { return (a-b)*(a<b?S:T); }
int main() {
scanf("%d %d %lld %lld", &N, &Q, &S, &T);
for (int i=0; i<=N; i++) scanf("%lld", &A[i]);
for (int i=1; i<=N; i++) now+=f(A[i-1], A[i]);
DS.init();
ll a, b;
for (int i=0; i<Q; i++) {
scanf("%d %d %lld", &L, &R, &X);
a=DS.get(L-1); b=DS.get(L);
now-=f(a, b);
if (R!=N) {
a=DS.get(R); b=DS.get(R+1);
now-=f(a, b);
}
DS.upd(L, R, X);
a=DS.get(L-1); b=DS.get(L);
now+=f(a, b);
if (R!=N) {
a=DS.get(R); b=DS.get(R+1);
now+=f(a, b);
}
printf("%lld\n", now);
}
return 0;
}
