#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <unordered_map>
#include <stack>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
#define ll long long
#define ld long double
#define inf (ll)(2*1e18)
//#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define pb push_back
#define endl "\n"
using namespace std;
void solve(){
ll n, q, s, t, i, in=0, dec=0, l, r, val;
cin>>n>>q>>s>>t;
vector<ll> a(n+1);
vector<ll> b(n);
for(i=0;i<=n;++i){
cin>>a[i];
}
for(i=0;i<n;++i){
b[i] = a[i+1] - a[i];
if(b[i] > 0){
dec += b[i];
}else{
in -= b[i];
}
}
for(i=0;i<q;++i){
cin>>l>>r>>val;
--l;
if(l >= 0){
if(b[l] > 0){
dec -= b[l];
}else{
in += b[l];
}
b[l] += val;
if(b[l] > 0){
dec += b[l];
}else{
in -= b[l];
}
}
if(r < n){
if(b[r] > 0){
dec -= b[r];
}else{
in += b[r];
}
b[r] -= val;
if(b[r] > 0){
dec += b[r];
}else{
in -= b[r];
}
}
cout<<in*t - dec*s<<endl;
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
srand(time(nullptr));
ll t=1;
// cin>>t;
for(;t>0;--t){
solve();
}
return 0;
}
