#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(), (a).end()
#define bit(s, i) (((s) >> (i)) & 1)
#define ii pair <int, int>
#define fi first
#define se second
#define int long long
#define ll long long
#define eb emplace_back
#define pb push_back
#define __builtin_popcount __builtin_popcountll
template <class X, class Y>
bool maximize(X &x, Y y) {
if(x < y) {
x = y;
return true;
}
return false;
}
template <class X, class Y>
bool minimize(X &x, Y y) {
if(x > y) {
x = y;
return true;
}
return false;
}
void solve();
int32_t main() {
#define task "test"
if(fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin.tie(0)->sync_with_stdio(0);
int tc = 1; //cin >> tc;
FOR(i, 1, tc){
solve();
}
}
const int N=2e5+5;
int n,q,s,t,cur,a[N];
ll st[N<<2];
void build(int id, int l, int r){
if(l==r){
st[id]=a[l];
return;
}
int mid=(l+r)>>1;
build(id<<1,l,mid);
build(id<<1|1,mid+1,r);
}
void build() {build(1,1,n);}
void down(int id){
if(st[id]==0) return;
st[id<<1]+=st[id];
st[id<<1|1]+=st[id];
st[id]=0;
}
void upd(int u, int v, int val, int id, int l, int r){
if(u>r||v<l) return;
if(u<=l&&r<=v){
st[id]+=val;
return;
}
down(id);
int mid=(l+r)>>1;
upd(u,v,val,id<<1,l,mid);
upd(u,v,val,id<<1|1,mid+1,r);
}
void upd(int u, int v, int val){upd(u,v,val,1,1,n);}
int get(int x){
int id=1, l=1, r=n;
while(true){
if(l==r) break;
down(id);
int mid=(l+r)>>1;
if(x<=mid){
id=id<<1;
r=mid;
}
else{
id=id<<1|1;
l=mid+1;
}
}
return st[id];
}
void solve() {
cin>>n>>q>>s>>t;
++n;
FOR(i,1,n) cin>>a[i];
FOR(i,1,n-1){
if(a[i+1]-a[i]>0){
cur=cur-(a[i+1]-a[i])*s;
}
else{
cur=cur-(a[i+1]-a[i])*t;
}
}
build();
FOR(i,1,q){
int l,r,x; cin>>l>>r>>x;
++l; ++r;
int tmp;
// cout<<cur<<'\n';
if(l>1){
tmp=get(l)-get(l-1);
if(tmp>0) cur=cur+tmp*s;
else cur=cur+tmp*t;
}
if(r<n){
tmp=get(r+1)-get(r);
if(tmp>0) cur=cur+tmp*s;
else cur=cur+tmp*t;
}
// cout<<cur<<'\n';
upd(l,r,x);
if(l>1){
tmp=get(l)-get(l-1);
if(tmp>0) cur=cur-tmp*s;
else cur=cur-tmp*t;
}
if(r<n){
tmp=get(r+1)-get(r);
if(tmp>0) cur=cur-tmp*s;
else cur=cur-tmp*t;
}
cout<<cur<<'\n';
}
}
