#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define pb push_back
#define endl "\n"
#define fr first
#define sc second
#define sz size()
#define ins insert
#define bc back()
#define str string
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update>
void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
const ll inf=1e18+7;
const ll mod=1e9;
const ll N=2e5+7;
const ld eps=1e-9;
vector<ll> t(N*4);
ll add[N*4],a[N],vv[N];
void build(ll v,ll tl,ll tr){
if(tl==tr){
t[v]=vv[tl];
return;
}
ll tm=(tl+tr)/2;
build(v*2,tl,tm);
build(v*2+1,tm+1,tr);
}
void push(ll v,ll tl,ll tr){
if(tl!=tr){
add[v*2]+=add[v];
add[v*2+1]+=add[v];
}
else t[v]+=add[v];
add[v]=0;
}
void upd(ll v,ll tl,ll tr,ll l,ll r,ll val){
push(v,tl,tr);
if(tl>r || tr<l) return;
if(l<=tl && tr<=r){
add[v]+=val;
push(v,tl,tr);
return;
}
ll tm=(tl+tr)/2;
upd(v*2,tl,tm,l,r,val);
upd(v*2+1,tm+1,tr,l,r,val);
}
ll get(ll v,ll tl,ll tr,ll pos){
push(v,tl,tr);
if(tl>pos || tr<pos)return -inf;
if(tl==tr){
return t[v];
}
ll tm=(tl+tr)/2;
return max(get(v*2,tl,tm,pos),get(v*2+1,tm+1,tr,pos));
}
void solve(){
ll i,j;
ll n,q,x,y;
cin>>n>>q>>x>>y;
for(i=1;i<=n+1;i++){
cin>>vv[i];
if(i>1){
a[i]=a[i-1]+(vv[i-1]-vv[i]<0 ? (vv[i-1]-vv[i])*x : (vv[i-1]-vv[i])*y);
}
}
build(1,1,n+1);
ll sum=a[n+1];
ll l,r,b;
n++;
for(i=0;i<q;i++){
cin>>l>>r>>b;
if(r+1==n){
ll l1=get(1,1,n,l),l2=get(1,1,n,l+1);
ll prev=l1-l2,cur=l1-(l2+b);
sum-=(prev<0 ? prev*x : prev*y);
sum+=(cur<0 ? cur*x : cur*y);
upd(1,1,n,l+1,r+1,b);
}else{
ll l1=get(1,1,n,l),l2=get(1,1,n,l+1),r1=get(1,1,n,r+1),r2=get(1,1,n,r+2);
ll prev=l1-l2,cur=l1-(l2+b);
sum-=(prev<0 ? prev*x : prev*y);
sum+=(cur<0 ? cur*x : cur*y);
prev=r1-r2,cur=(r1+b)-r2;
sum-=(prev<0 ? prev*x : prev*y);
sum+=(cur<0 ? cur*x : cur*y);
upd(1,1,n,l+1,r+1,b);
}
cout<<sum<<endl;
}
}
signed main(){
start();
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
ll t=1;
//cin>>t;
while(t--) solve();
}
/*
*/
