/*#pragma GCC optimize("O3")
#pragma GCC optimization("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")*/
#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 1000000000000000000
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
mt19937 rng(time(0));
ll randll(ll l, ll r){
return uniform_int_distribution<ll>(l, r)(rng);
}
vll tree;
void bt(ll v, ll tl, ll tr, vll& a) {
if (tl == tr) {
tree[v] = a[tl];
return;
}
ll tm = (tl+tr)/2;
bt(v*2, tl, tm, a);
bt(v*2+1, tm+1, tr, a);
}
void upd(ll l, ll r, ll d, ll v, ll tl, ll tr) {
if (l <= tl && tr <= r) {
tree[v] += d;
return;
}
if (tl > r || tr < l) return;
ll tm = (tl+tr)/2;
upd(l, r, d, v*2, tl, tm);
upd(l, r, d, v*2+1, tm+1, tr);
}
ll get(ll idx, ll v, ll tl, ll tr) {
if (tl == tr) return tree[v];
ll tm = (tl+tr)/2;
if (idx <= tm) return tree[v]+get(idx, v*2, tl, tm);
return tree[v]+get(idx, v*2+1, tm+1, tr);
}
int main(){
speed;
srand(time(0));
ll n, q, s, t;
cin >> n >> q >> s >> t;
vll a(n+1);
ll res = 0;
for (int i = 0; i < n+1; i ++) {
cin >> a[i];
}
tree.resize(n*4+7, 0);
bt(1, 0, n, a);
for (int i = 0; i < n; i ++) {
if (a[i] < a[i+1]) res -= (a[i+1]-a[i])*s;
else res += (a[i]-a[i+1])*t;
}
//cout << res << endl;
while (q --) {
ll l, r, d;
cin >> l >> r >> d;
ll k = get(l-1, 1, 0, n), k1 = get(l, 1, 0, n);
if (k < k1) res += (k1-k)*s;
else res -= (k-k1)*t;
k = get(r, 1, 0, n), k1 = get(r+1, 1, 0, n);
if (k < k1) res += (k1-k)*s;
else res -= (k-k1)*t;
upd(l, r, d, 1, 0, n);
k = get(l-1, 1, 0, n), k1 = get(l, 1, 0, n);
if (k < k1) res -= (k1-k)*s;
else res += (k-k1)*t;
k = get(r, 1, 0, n), k1 = get(r+1, 1, 0, n);
if (k < k1) res -= (k1-k)*s;
else res += (k-k1)*t;
cout << res << endl;
}
}
