/*
_ ________ ___ __ ___ _ _ _
| | / /| _ \ / _ \ / // _ \ | | | |(_)
| |/ / | | | |/ /_\ \ / // /_\ \| | __ __ _ | | _
| \ | | | || _ | / / | _ || |/ // _` || || |
| |\ \| |/ / | | | | / / | | | || <| (_| || || |
\_| \_/|___/ \_| |_//_/ \_| |_/|_|\_\\__,_||_||_|
*/
#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5+50;
const int mod = 1e9+7;
#define pb push_back
const int in = 1e9+9;
typedef pair<int,int> ii;
int n, q, s, t;
int d[N], wind = 0, ans[N];
#define fi first
#define se second
signed main(){
cin >> n >> q >> s >> t;
int cur = 0;
for(int i=0;i<=n;i++){
cin >> d[i];
d[i] = d[i] - cur;
cur = d[i] + cur;
}
for(int i=1;i<=n;i++){
if(d[i]>0) wind -= d[i] * s;
else wind -= d[i] * t;
}
for(int i=1;i<=q;i++){
int a, b, x;
cin >> a >> b >> x;
if(d[a] > 0) wind += d[a] * s;
else wind += d[a] * t;
if(b != n) {
if(d[b+1]>0) wind += d[b+1] * s;
else wind += d[b+1] * t;
}
d[a] += x;
d[b+1] -= x;
if(d[a] > 0) wind -= d[a] * s;
else wind -= d[a] * t;
if(b!=n) {
if(d[b+1]>0) wind -= d[b+1] * s;
else wind -= d[b+1] * t;
}
ans[i] = wind;
}
for(int i=1;i<=q;i++) cout << ans[i] << "\n";
return 0;
}
