// 23 - 12 - 23
#include<bits/stdc++.h>
using namespace std;
#define read() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define day() time_t now = time(0);char* x = ctime(&now);cerr<<"Right Now Is : "<<x<<"\n"
#define int long long
#define ii pair<int,int>
#define X first
#define Y second
const long long MAX = (int)2e5 + 5;
const long long INF = (int)1e9;
const long long MOD = (int)1e9 + 7;
int n,q,a[MAX],s,t,ans = 0;
int bit[MAX];
void update(int id,int val){
if(id > n)return;
for(;id <= n;id += id & -id)bit[id] += val;
}
int get(int id){
int sum = 0;
if(id == 0)return 0;
for(;id > 0;id -= id & -id)sum += bit[id];
return sum;
}
void uprange(int l,int r,int val){
update(l,val);
update(r + 1,-val);
}
signed main(){
read();
cin >> n >> q >> s >> t;
for(int i = 0;i <= n;i++){
cin >> a[i];
if(i)
uprange(i,i,a[i]);
if(i)
if(a[i] > a[i - 1])ans -= (a[i] - a[i - 1]) * s;
else ans -= (a[i] - a[i - 1]) * t;
}
//cout << ans << '\n';
for(int i = 1,l,r,x;i <= q;i++){
cin >> l >> r >> x;
int xx = get(l);
int yy = get(l - 1);
if(xx > yy){
ans += (xx - yy) * s;
}else{
ans += (xx - yy) * t;
}
xx = get(r + 1);
yy = get(r);
if(r < n){
if(xx > yy){
ans += (xx - yy) * s;
}else{
ans += (xx - yy) * t;
}
}
uprange(l,r,x);
xx = get(l);
yy = get(l - 1);
if(xx > yy){
ans -= (xx - yy) * s;
}else{
ans -= (xx - yy) * t;
}
xx = get(r + 1);
yy = get(r);
if(r < n){
if(xx > yy){
ans -= (xx - yy) * s;
}else{
ans -= (xx - yy) * t;
}
}
cout << ans << '\n';
}
}
