#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef tuple<ll,ll,ll> trio;
typedef pair<int,int> pii;
const int MAXN = 2e5+5;
const ll INF = 1e9;
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mk make_pair
#define pb push_back
#define fr first
#define sc second
int n, q, s, t, a[MAXN];
ll ans, seg[4*MAXN], lazy[4*MAXN], dif[MAXN];
void build(int node, int l, int r) {
if(l == r) {
seg[node] = a[l];
return;
}
int mid = (l+r)/2;
build(2*node, l, mid);
build(2*node+1, mid+1, r);
}
void prop(int node, int flag) {
seg[node] += lazy[node];
if(!flag) {
lazy[2*node] += lazy[node];
lazy[2*node+1] += lazy[node];
}
lazy[node] = 0;
}
void update(int node, int l, int r, int p, int q, int x) {
prop(node, l==r);
if(r < p or q < l) return;
if(p <= l and r <= q) {
lazy[node] = x;
prop(node, l==r);
return;
}
int mid = (l+r)/2;
update(2*node, l, mid, p, q, x);
update(2*node+1, mid+1, r, p, q, x);
}
ll query(int node, int l, int r, int ind) {
prop(node, l == r);
if(ind == 0) return 0;
if(l == r) return seg[node];
int mid = (l+r)/2;
if(ind <= mid) return query(2*node, l, mid, ind);
else return query(2*node+1, mid+1, r, ind);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> q >> s >> t;
for(int i = 0; i <= n; i++) {
cin >> a[i];
if(i == 0) continue;
if(a[i] > a[i-1]) dif[i] = (ll)(a[i-1] - a[i]) * s;
else dif[i] = (ll)(a[i-1] - a[i]) * t;
ans += dif[i];
}
build(1, 1, n);
while(q--) {
int L, R, X;
cin >> L >> R >> X;
update(1, 1, n, L, R, X);
ans -= dif[L];
dif[L] = query(1, 1, n, L-1) - query(1, 1, n, L);
if(dif[L] < 0) dif[L] *= s;
else dif[L] *= t;
ans += dif[L];
ans -= dif[R+1];
dif[R+1] = query(1, 1, n, R) - query(1, 1, n, min(R+1, n));
if(dif[R+1] < 0) dif[R+1] *= s;
else dif[R+1] *= t;
ans += dif[R+1];
cout << ans << "\n";
}
}
