#include <bits/stdc++.h>
#define ll long long
#define MAXN 200010
using namespace std;
ll a[MAXN];
struct bit
{
vector<ll> v;
void Init()
{
v.resize(MAXN,0ll);
}
void Add(ll pos,ll val)
{
for (ll i=pos;i<MAXN;i+=i&(-i))
v[i]+=val;
}
ll Calc(ll pos)
{
ll sum=0;
for (ll i=pos;i>0;i-=i&(-i))
sum+=v[i];
return sum;
}
ll Query(ll l,ll r)
{
return Calc(r)-Calc(l-1);
}
};
bit b;
int main()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
ll n,q,s,t,ans=0,l,r,x;
cin >> n >> q >> s >> t;
for (ll i=0;i<=n;i++)
{
cin >> a[i];
if (i)
{
if (a[i]>a[i-1])
ans-=s*(a[i]-a[i-1]);
else
ans+=t*(a[i-1]-a[i]);
}
}
b.Init();
while (q--)
{
cin >> l >> r >> x;
if (l)
{
ll val1=a[l-1]+b.Query(1,l-1),val2=a[l]+b.Query(1,l);
if (val1<val2)
ans+=s*(val2-val1);
else
ans-=t*(val1-val2);
}
r++;
if (r<=n)
{
ll val1=a[r-1]+b.Query(1,r-1),val2=a[r]+b.Query(1,r);
if (val1<val2)
ans+=s*(val2-val1);
else
ans-=t*(val1-val2);
}
b.Add(l,x);
b.Add(r,-x);
if (l)
{
ll val1=a[l-1]+b.Query(1,l-1),val2=a[l]+b.Query(1,l);
if (val1<val2)
ans-=s*(val2-val1);
else
ans+=t*(val1-val2);
}
if (r<=n)
{
ll val1=a[r-1]+b.Query(1,r-1),val2=a[r]+b.Query(1,r);
if (val1<val2)
ans-=s*(val2-val1);
else
ans+=t*(val1-val2);
}
cout << ans << "\n";
}
return 0;
}
