#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ff(i,a,b) for(int i=a;i<=b;i++)
#define fb(i,b,a) for(int i=b;i>=a;i--)
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 200005;
const int inf = 1e9 + 5;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
int n, q, S, T;
int niz[maxn];
ll A[maxn];
int main()
{
ios::sync_with_stdio(false);
cout.tie(nullptr);
cin.tie(nullptr);
cin >> n >> q >> S >> T;
ff(i,0,n)cin >> niz[i];
ff(i,1,n)A[i] = niz[i] - niz[i - 1];
ll uk = 0;
ff(i,1,n){
if(A[i] >= 0)uk -= 1ll * S * A[i];
else uk -= 1ll * T * A[i];
}
while(q--){
int L, R, X;
cin >> L >> R >> X;
if(A[L] >= 0)uk += 1ll * S * A[L];
else uk += 1ll * T * A[L];
A[L] += X;
if(A[L] >= 0)uk -= 1ll * S * A[L];
else uk -= 1ll * T * A[L];
if(R < n){
if(A[R + 1] >= 0)uk += 1ll * S * A[R + 1];
else uk += 1ll * T * A[R + 1];
A[R + 1] -= X;
if(A[R + 1] >= 0)uk -= 1ll * S * A[R + 1];
else uk -= 1ll * T * A[R + 1];
}
cout << uk << endl;
}
return 0;
}
/**
3 1 1 2
0 4 1 8
1 2 2
// probati bojenje sahovski ili slicno
**/
