#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';
}
}
/*
Thuong em khi mua thu
Thuong em sang mua ha
Thuong em bang qua mua dong,gui gio xuan om em vao long
Thuong em bao mua mua
Tham thuong luon bao mua nang
Thuong yeu em khong doi thay,gio mat em tim toi hao gay ):
*/
