#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimization("unroll-loops")
// #pragma ("reroll")
#define all(v) v.begin(), v.end()
#define skip continue;
#define gold ios_base::sync_with_stdio(false);cin.tie(NULL);
#define xa "\n"
#define int long long
#define pb push_back
#define S second
#define F first
using namespace std;
const int mod = 1e9 + 7;
const int N = 1e6 + 7;
const int MAX = 1e9;
const int inf = 1e18;
int gcd(int a, int b) { if (b == 0) return a; else if(a == 0) return b; else return gcd(b, a % b); }
int lcm(int a, int b) { return a / gcd(a, b) * b; }
int a[N];
void solve() {
int n, q, s, t;
cin >> n >> q >> s >> t;
for(int i = 0; i <= n; i++){
cin >> a[i];
}
while(q--){
int l, r, x;
cin >> l >> r >> x;
if(l <= n && n <= r){
a[n] += x;
}
cout << (a[0] - a[n]) * s << xa;
}
}
signed main() {
gold;
//freopen("knight.in", "r", stdin);
//freopen("knight.out", "w", stdout);
int t = 1;
int tt = 0;
//cin >> t;
while (t--) {
tt++;
//cout << "Case " << tt << ":" << xa;
solve();
}
}
