#include<bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
#define F first
#define S second
typedef long long ll;
typedef pair<int, int> pii;
const int N=2e5+5;
int n, q, s, t, a[N];
ll ans;
struct fenwick{
vector<ll>bit;
void add(int i, int val){
for(;i<=n;i|=(i+1))
bit[i]+=val;
}
void add(int l, int r, int val){
add(l, val);
add(r, -val);
}
ll sum(int i){
ll res=0;
for(;i>=0;i=(i&(i+1))-1)
res+=bit[i];
return res;
}
} A;
inline ll num(int i){
return A.sum(i)+a[i];
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n>>q>>s>>t;
for(int i=0;i<=n;++i)
cin>>a[i];
for(int i=1;i<=n;++i){
if(a[i]>a[i-1])
ans-=1LL*(a[i]-a[i-1])*s;
else
ans+=1LL*(a[i-1]-a[i])*t;
}
A.bit.assign(n+1, 0);
while(q--){
int l, r, x;
cin>>l>>r>>x;
ll y=num(l-1), z=num(l);
if(z>y)
ans+=1LL*(z-y)*s;
else
ans-=1LL*(y-z)*t;
z+=x;
if(z>y)
ans-=1LL*(z-y)*s;
else
ans+=1LL*(y-z)*t;
if(r<n){
y=num(r);z=num(r+1);
if(z>y)
ans+=1LL*(z-y)*s;
else
ans-=1LL*(y-z)*t;
y+=x;
if(z>y)
ans-=1LL*(z-y)*s;
else
ans+=1LL*(y-z)*t;
}
A.add(l, r+1, x);
cout<<ans<<'\n';
}
}
