#include<bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define int long long
#define endl '\n'
#define pi acos(-1)
#define pque priority_queue
#define N 1000000
#define lmax LONG_LONG_MAX
typedef pair < int, int > ii;
typedef vector < int > vi;
typedef vector < vi > vii;
int mod = 1000000007;
int n, q, s, t, a[1000009], f[1000009], sums, sumt, l, r, x;
signed main()
{
//ios_base::sync_with_stdio(0);
cin >> n >> q >> s >> t;
for(int i = 0; i <= n; i++)
cin >> a[i];
for(int i = 1; i <= n; i++)
{
f[i] = a[i] - a[i - 1];
if(f[i] > 0)
sums += f[i];
else
sumt -= f[i];
}
while(q--)
{
cin >> l >> r >> x;
if(f[l] > 0)
sums -= f[l];
else
sumt += f[l];
if(r < n)
{
if(f[r + 1] > 0)
sums -= f[r + 1];
else
sumt += f[r + 1];
}
f[l] += x;
f[r + 1] -= x;
if(f[l] > 0)
sums += f[l];
else
sumt -= f[l];
if(r < n)
{
if(f[r + 1] > 0)
sums += f[r + 1];
else
sumt -= f[r + 1];
}
cout << sumt * t - sums * s << endl;
}
}
