/// slava sovet·skomu soyuzu
#include <bits/stdc++.h>
using namespace std;
using db = long double;
#define int long long
#define ll long long
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
const int mod = 1000000007;
const int maxN = 200005;
const int base = 31;
const ll infty = 1000000000000000000;
int n,q,s,t;
int a[maxN];
int b[maxN];
void read()
{
cin >> n >> q >> s >> t;
for(int i = 0;i <= n;i++)
{
cin >> a[i];
}
int res = 0;
for(int i = 1;i <= n;i++)
{
if(a[i] > a[i-1]) res -= s * (a[i] - a[i-1]);
else res -= t * (a[i] - a[i-1]);
b[i] = a[i] - a[i-1];
}
while(q--)
{
int L,R,x;
cin >> L >> R >> x;
if(b[L] > 0) res += s * b[L];
else res += t * b[L];
if(R < n)
{
if(b[R+1] > 0) res += s * b[R+1];
else res += t * b[R+1];
}
b[L] += x;
b[R+1] -= x;
if(b[L] > 0) res -= s * b[L];
else res -= t * b[L];
if(R < n)
{
if(b[R+1] > 0) res -= s * b[R+1];
else res -= t * b[R+1];
}
cout << res <<'\n';
}
}
void sol()
{
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//freopen("test.inp","r",stdin);
int tests;
//cin >> tests;
tests = 1;
while (tests--)
{
read();
sol();
}
return 0;
}
