#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define ertunt return
const int MOD = 998244353;
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
int main() {
ll n,q,s,t;
cin >> n >> q >> s >> t;
ll a[n+4];
ll ans = 0;
ll b[n+4];
for(ll i = 0; i <= n; i++){
cin >> a[i];
if(i > 0){
b[i] = a[i] - a[i-1];
if(a[i] >= a[i-1]){
ans-=b[i]*s;
}
else{
ans+=t*(a[i-1] - a[i]);
}
}
}
while(q--){
ll l,r,x;
cin >> l >> r >> x;
if(b[l] >= 0)ans+=s*b[l];
else ans += t*b[l];
b[l]+=x;
if(b[l]>=0) ans-=s*b[l];
else ans-=t*b[l];
if(r < n){
if(b[r+1]>=0) ans+=s*b[r+1];
else ans+=t*b[r+1];
b[r+1]-=x;
if(b[r+1]>=0) ans-=s*b[r+1];
else ans-=t*b[r+1];
}
cout << ans << '\n';
}
}
