#include <bits/stdc++.h>
#define mod 1000000007
#define pb push_back
#define mid(l, r) ((l)+(r))/2
#define len(a) (a).length()
#define sz(a) (a).size()
#define xx first
#define yy second
#define inf int(2e9)
#define ff(i, a, b) for(int (i) = (a); (i) <= (b); ++(i))
#define fb(i, a, b) for(int (i) = (a); (i) >= (b); --(i))
#define maxn 200005
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
template<class T>
void print(const T niz[], const int siz)
{
for(int i=0;i<siz;i++)
cout << niz[i] << " ";
cout << endl;
}
int n,q;
ll s,t;
ll niz[maxn];
ll seg[4*maxn];
ll lazy[4*maxn];
ll go,dl;
void init(int node, int l, int r){
if(l == r){
seg[node] = niz[l];
return;
}
int mid = (l + r) / 2;
init(node*2,l,mid);
init(node*2+1,mid+1,r);
seg[node] = seg[node * 2] + seg[node * 2 + 1];
}
void propage(int node, int l, int r){
seg[node] += (r - l + 1) * lazy[node];
if(l < r){
lazy[node * 2] += lazy[node];
lazy[node * 2 + 1] += lazy[node];
}
lazy[node] = 0;
}
void update(int node, int l, int r, int levo, int desno, ll val){
propage(node, l, r);
if(r < levo || l > desno)return;
if(l >= levo && r <= desno){
lazy[node] += val;
propage(node, l, r);
return;
}
int mid = (l + r) / 2;
update(node*2,l,mid,levo,desno,val);
update(node*2+1,mid+1,r,levo,desno,val);
propage(node*2,l,mid);
propage(node*2+1,mid+1,r);
seg[node] = seg[node * 2] + seg[node * 2 + 1];
}
ll query(int node, int l, int r, int poz){
propage(node,l,r);
if(l == r)return seg[node];
int mid = (l + r) / 2;
if(poz <= mid)return query(node*2,l,mid,poz);
else return query(node*2+1,mid+1,r,poz);
}
ll get(int x){
if(x == 0)return 0;
return query(1,1,n,x);
}
int main()
{
ios_base::sync_with_stdio(false);
cin >> n >> q >> s >> t;
ff(i,0,n)cin >> niz[i];
ff(i,0,n - 1){
if(niz[i] < niz[i + 1])go += (niz[i+1] - niz[i]);
else dl += (niz[i] - niz[i + 1]);
}
init(1,1,n);
while(q--){
int l,r;
ll x;
cin >> l >> r >> x;
ll a,b,c,d=1e9;
a = get(l-1);
b = get(l);
c = get(r);
if(r != n)d = get(r+1);
if(a < b)go -= (b-a);
else dl -= (a-b);
b += x;
if(a < b)go += (b-a);
else dl += (a-b);
if(r != n){
if(c < d)go -= (d-c);
else dl -= (c-d);
c += x;
if(c < d)go += (d-c);
else dl += (c-d);
}
cout << dl*t - s*go << endl;
update(1,1,n,l,r,x);
}
return 0;
}
