#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll base = 1<<18;
ll tree[2*base];
void zmien(ll a, ll b, ll v){
a+=base-1;
b+=base+1;
while(a/2!=b/2){
if (!(a&1))tree[a+1]+=v;
if (b&1)tree[b-1]+=v;
a>>=1;
b>>=1;
}
}
ll sprawdz(ll v){
v+=base;
ll ans=0;
while(v){
ans+=tree[v];
v>>=1;
}
return ans;
}
ll cur=0,n,q,s,t;
void change_wind(ll v, ll diff){
if (v==n+1)return;
ll h1=sprawdz(v-1),h2=sprawdz(v);
if (h1<h2)cur+=(h2-h1)*s;
else cur+=(h2-h1)*t;
if (h1<h2+diff)cur-=(h2+diff-h1)*s;
else cur-=(h2+diff-h1)*t;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll a,b,c;
cin >> n >> q >> s >> t;
for (ll i = 0; i<=n; i++){
cin >> tree[base+i];
}
for (ll i = 1; i<=n; i++){
if ((tree[base+i]>tree[base+i-1]))cur-=(tree[base+i]-tree[base+i-1])*s;
else cur-=(tree[base+i]-tree[base+i-1])*t;
}
for (ll i = 1; i<=q; i++){
cin >> a >> b >> c;
change_wind(a,c);
change_wind(b+1,-c);
zmien(a,b,c);
cout << cur << '\n';
}
}
