#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define pi pair<int,int>
#define sz(v) (int)(v).size()
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
template<class T> using upq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int lwrbound(const vector<T>& a, const T& b, const int s = 0){return int(lower_bound(s + all(a), b) - a.begin());}
template<class T> int uprbound(const vector<T>& a, const T& b, const int s = 0){return int(upper_bound(s + all(a), b) - a.begin());}
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define sumof(x) accumulate(all(x), 0ll)
#define dbg(x) "[" << #x " = " << (x) << "]"
#define el "\n"
using ll = long long;
using ld = long double;
template<class T> bool ckmx(T& a, const T b){return (a < b ? a = b, true : false);}
template<class T> bool ckmn(T& a, const T b){return (a > b ? a = b, true : false);}
const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = numeric_limits<ll>::max() / 8;
#define int long long
void Main()
{
int n, q, S, T; cin >> n >> q >> S >> T;
vi a(n + 1); FOR(i, 0, n) cin >> a[i];
vi dif(n + 1); FOR(i, 1, n) dif[i] = a[i] - a[i - 1];
ll answer = 0;
auto upd = [&](int x, int op) -> void{
answer += 1ll * op * (dif[x] > 0 ? -S : +T) * abs(dif[x]);
};
FOR(i, 1, n) upd(i, +1);
while(q--){
int l,r,x; cin >> l >> r >> x;
upd(l, -1), dif[l] += x, upd(l, +1);
if(r < n){
upd(r + 1, -1), dif[r + 1] -= x, upd(r + 1, +1);
}
cout << answer << el;
}
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#define name "InvMOD"
if(fopen(name".INP", "r")){
freopen(name".INP", "r", stdin);
freopen(name".OUT", "w", stdout);
}
int t = 1; while(t--) Main();
return 0;
}
