#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define lowbit(x) x&-x
const int N = 998244353;
const int maxn = 2e5 + 5;
ll BIT[maxn];
void upd(int pos, int val){
pos++;
while(pos < maxn){
BIT[pos] += val;
pos += lowbit(pos);
}
}
ll qry(int pos){
pos++;
ll ret = 0;
while(pos > 0){
ret += BIT[pos];
pos -= lowbit(pos);
}
return ret;
}
int main(void){
fastio;
int n, q, s, t;
cin>>n>>q>>s>>t;
for(int i = 0; i <= n; i++){
int x;
cin>>x;
upd(i, x);
upd(i + 1, -x);
}
ll ans = 0;
auto cost = [&](ll a, ll b) -> ll{
if(a < b) return - s * (b - a);
else return t * (a - b);
};
for(int i = 1; i <= n; i++){
ll a = qry(i - 1), b = qry(i);
ans += cost(a, b);
}
for(int i = 0; i < q; i++){
int l, r, x;
cin>>l>>r>>x;
ans -= cost(qry(l - 1), qry(l));
if(r != n) ans -= cost(qry(r), qry(r + 1));
upd(l, x);
upd(r + 1, -x);
ans += cost(qry(l - 1), qry(l));
if(r != n) ans += cost(qry(r), qry(r + 1));
cout<<ans<<"\n";
}
}
