#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define Mp make_pair
#define sep ' '
#define endl '\n'
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define kill(res) cout << res << '\n', exit(0);
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 2e5 + 50;
const ll Mod = 1e9 + 7;
ll n, q, S, T, arr[N], delta[N], res;
void upd(int i, int x){
if(delta[i] >= 0) res += delta[i] * S;
else res += delta[i] * T;
delta[i] += x;
if(delta[i] >= 0) res -= delta[i] * S;
else res -= delta[i] * T;
}
int main(){
fast_io;
cin >> n >> q >> S >> T;
for(int i = 0; i <= n; i++){
cin >> arr[i];
if(i) delta[i] = arr[i] - arr[i-1];
}
for(int i = 1; i <= n; i++){
if(delta[i] >= 0) res -= delta[i] * S;
else res -= delta[i] * T;
}
while(q--){
int l, r, x;
cin >> l >> r >> x;
upd(l, x);
if(r < n) upd(r+1, -x);
cout << res << endl;
}
}
