#include <iostream>
#include <vector>
#include <bitset>
#include <queue>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <stack>
#include <set>
#include <map>
#include <cassert>
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
#define ii pair<int,int>
#define pll pair<long long, long long>
#define fi first
#define se second
#define r first
#define c second
#define all(x) x.begin(), x.end()
ostream& operator << (ostream& os, pair<int, int> a) {
return os << a.first << " : " << a.second;
}
#define endl '\n'
#define db(val) "["#val" = "<<(val)<<"] "
#define cntbit(x) __builtin_popcount(x)
const int N = 2e5 + 5;
const int iINF = 1e9;
const ll MOD = 1e9 + 7;
const ll MOD2 = 998244353;
const ll INF = 1e18;
int n, q;
ll s, t;
int a[N];
ll A[N], S[N];
void upd(ll bit[N], int v, ll val) {
for (; v <= n; v += v & -v) bit[v] += val;
}
ll get(ll bit[N], int v) {
ll res = 0;
for (;v >= 1; v -= v & -v) res += bit[v];
return res;
}
ll point(ll bit[N], int v) {return get(bit, v) - get(bit, v - 1);}
int main() {
#ifdef CHUNGDINH
freopen("main.inp","r",stdin);
//freopen("main.out","w",stdout);
#endif
memset(A, 0ll, sizeof A);
memset(S, 0ll, sizeof S);
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; i++) {
cin >> a[i];
}
for (int i = 1; i <= n; i++) {
upd(A, i, a[i] - a[i - 1]);
ll tt;
if (a[i] <= a[i - 1]) tt = t*(a[i - 1] - a[i]);
else tt = -s*(a[i] - a[i - 1]);
upd(S, i, tt);
// cout << get(S, i) << " ";
} //cout << endl;
while (q--) {
int l, r; ll x;
cin >> l >> r >> x;
// for (int i = 1; i <= n; i++) cout << get(S, i) - get(S, i - 1) << " "; cout << endl;
//range update
upd(A, l, x); upd(A, r + 1, -x);
//for (int i = 1; i <= n; i++) cout << get(A, i) - get(A, i - 1) << " "; cout << endl;
ll tt;
ll tt1;
{ // l is always >= 1
tt1 = point(A, l);
//cout << tt1 << endl;
if (tt1 > 0) tt = -s*(tt1);
else tt = t*(-tt1);
upd(S, l, -point(S, l) + tt);
}
if (r + 1 <= n) {
tt1 = point(A, r + 1);
if (tt1 > 0) tt = -s*(tt1);
else tt = t*(-tt1);
upd(S, r + 1, -point(S, r + 1) + tt);
}
//for (int i = 1; i <= n; i++) cout << get(S, i) - get(S, i - 1) << " "; cout << endl;
cout << get(S, n) << endl;
}
}
/*
Array bounds *
long long vs int
Garbage value
Sometimes, VNOI views "arrays out of bounds" as "wrong answer"
*/
