#include <bits/stdc++.h>
#define f first
#define s second
#define ll long long
using namespace std;
const int maxn=2e5+5;
const int INF=1e18;
int n,q,s,t;
ll a[maxn];
ll lazy[4*maxn];
struct node{
ll sum;
ll val;
};
node tree[4*maxn];
node mergeNode(node L,node R)
{
node res;
res.sum=L.sum+R.sum;
res.val=max(L.val,R.val);
return res;
}
void build(int id,int l,int r)
{
if(l==r){
if(a[l]-a[l-1]>0) tree[id].sum=-1LL*(a[l]-a[l-1])*s;
else tree[id].sum=1LL*(a[l-1]-a[l])*t;
tree[id].val=a[l];
return;
}
int mid=(l+r)/2;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
tree[id]=mergeNode(tree[id*2],tree[id*2+1]);
}
void down(int id)
{
ll d=lazy[id];
tree[id*2].val+=d;
tree[id*2+1].val+=d;
lazy[id*2]+=d;
lazy[id*2+1]+=d;
lazy[id]=0;
}
void update_p(int id,int l,int r,int pos,ll d)
{
if(r<pos||pos<l) return;
if(l==r){
tree[id].sum=d;
return;
}
int mid=(l+r)/2;
down(id);
update_p(id*2,l,mid,pos,d);
update_p(id*2+1,mid+1,r,pos,d);
tree[id]=mergeNode(tree[id*2],tree[id*2+1]);
}
void update(int id,int l,int r,int u,int v,ll d)
{
if(r<u||v<l) return;
if(u<=l&&r<=v){
tree[id].val+=d;
lazy[id]+=d;
return;
}
int mid=(l+r)/2;
down(id);
update(id*2,l,mid,u,v,d);
update(id*2+1,mid+1,r,u,v,d);
tree[id]=mergeNode(tree[id*2],tree[id*2+1]);
}
node get(int id,int l,int r,int u,int v)
{
if(r<u||v<l) return {0,-INF};
if(u<=l&&r<=v) return tree[id];
int mid=(l+r)/2;
down(id);
return mergeNode(get(id*2,l,mid,u,v),get(id*2+1,mid+1,r,u,v));
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>q>>s>>t;
for(int i=0;i<=n;i++) cin>>a[i];
build(1,1,n);
while(q--){
int l,r,x;
cin>>l>>r>>x;
update(1,1,n,l,r,x);
ll a2=get(1,1,n,l,l).val;
ll a1;
if(l>1) a1=get(1,1,n,l-1,l-1).val;
else a1=0;
if(a1>a2) update_p(1,1,n,l,1LL*(a1-a2)*t);
else update_p(1,1,n,l,-1LL*(a2-a1)*s);
if(r<n){
a1=get(1,1,n,r,r).val;
a2=get(1,1,n,r+1,r+1).val;
if(a1>a2) update_p(1,1,n,r+1,1LL*(a1-a2)*t);
else update_p(1,1,n,r+1,-1LL*(a2-a1)*s);
}
cout<<get(1,1,n,1,n).sum<<'\n';
}
}
