#include<bits/stdc++.h>
using namespace std;
#define INIT ios_base :: sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define mp make_pair
#define pb push_back
#define ft first
#define sc second
#define ll long long
#define pii pair<int, int>
#define count_bits __builtin_popcount
#define int ll
int n, q, s, t, a[200010];
int neg=0, pos=0;
int seg[800010];
void lazy(int v){
seg[2*v]+=seg[v]; seg[2*v+1]+=seg[v];
seg[v]=0;
return;
}
void update(int v, int tl, int tr, int l, int r, int x){
if(l>r){
return;
}
if( (l==tl) && (r==tr) ){
seg[v]+=x; return;
}
lazy(v);
int mid=(tl+tr)>>1ll;
update(v*2, tl, mid, l,min(r, mid), x); update(2*v+1, mid+1, tr, max(l, mid+1), r, x);
}
int query(int v, int tl, int tr, int p){
if(tl==tr){
return seg[v];
}
int mid=(tl+tr)>>1ll;
lazy(v);
if(p<=mid){
return query(2*v, tl, mid, p);
}
else{
return query(2*v+1, mid+1, tr, p);
}
}
int32_t main(){
INIT
cin>>n>>q>>s>>t;
for(int i=0; i<=n; i++){
cin>>a[i];
if(i>0){
if( (a[i])>a[i-1] ){
pos+=(a[i]-a[i-1]);
}
else{
neg+=(a[i]-a[i-1]);
}
}
}
//cout<<neg<<" "<<pos<<"\n";
while(q--){
int l, r, x; cin>>l>>r>>x;
int a1=a1=( (l-1)>0 )?(query(1, 1, n, l-1)+a[l-1]):(0), a2=query(1, 1, n, l)+a[l];
int a3=query(1, 1, n, r)+a[r], a4=query(1, 1, n, min(r+1, n))+a[min(r+1, n)];
//cout<<a1<<" "<<a2<<" "<<a3<<" "<<a4<<"\n";
if( (a2>a1) ){
pos-=a2-a1;
}
else{
neg-=a2-a1;
}
if( (a4>a3) ){
pos-=a4-a3;
}
else{
neg-=a4-a3;
}
update(1, 1, n, l, r, x);
a1=( (l-1)>0 )?(query(1, 1, n, l-1)+a[l-1]):(0), a2=query(1, 1, n, l)+a[l];
a3=query(1, 1, n, r)+a[r], a4=query(1, 1, n, min(r+1, n))+a[min(r+1, n)];
if( (a2>a1) ){
pos+=a2-a1;
}
else{
neg+=a2-a1;
}
if( (a4>a3) ){
pos+=a4-a3;
}
else{
neg+=a4-a3;
}
//cout<<a1<<" "<<a2<<" "<<a3<<" "<<a4<<"\n";
cout<<(t*(-neg)-s*pos)<<"\n";
}
return 0;
}
