#include <bits/stdc++.h>
using namespace std;
int n,q,s,t,altitude[200009];
struct node {
long long front,back,temp;
};
node st[200009 * 4];
long long lazy[200009 * 4];
long long cost(long long ai,long long ai1) {
if (ai < ai1) return s * (ai - ai1);
return t * (ai - ai1);
}
void build(int id,int l,int r) {
if (l == r) {
st[id] = {altitude[l],altitude[r],0};
return;
}
int mid = (l + r) >> 1;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
st[id] = {st[id*2].front,st[id*2+1].back,
st[id*2].temp + st[id*2+1].temp + cost(st[id*2].back,st[id*2+1].front)};
}
void changenode(int id,long long val) {
st[id].front += val;
st[id].back += val;
lazy[id] += val;
}
void push_down(int id) {
changenode(id*2,lazy[id]);
changenode(id*2+1,lazy[id]);
lazy[id] = 0;
}
void update(int id,int l,int r,int u,int v,int val) {
if (l > v || r < u) return;
if (l >= u && r <= v) {
changenode(id,val);
return;
}
int mid = (l + r) >> 1;
push_down(id);
update(id*2,l,mid,u,v,val);
update(id*2+1,mid+1,r,u,v,val);
st[id] = {st[id*2].front,st[id*2+1].back,
st[id*2].temp + st[id*2+1].temp + cost(st[id*2].back,st[id*2+1].front)};
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(nullptr);
// freopen(".inp","r",stdin);
// freopen(".out","w",stdout);
cin >> n >> q >> s >> t;
for (int i = 0;i <= n;i++) cin >> altitude[i];
build(1,1,n);
while (q--) {
int l,r,x;cin >> l >> r >> x;
update(1,1,n,l,r,x);
cout << st[1].temp + cost(0,st[1].front) << '\n';
}
}
