#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define replr(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define reprl(i, a, b) for (int i = int(a); i >= int(b); --i)
#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define mkp(a, b) make_pair(a, b)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VPI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<VPI> VVPI;
typedef pair<ll, ll> PLL;
typedef vector<ll> VL;
typedef vector<PLL> VPL;
typedef vector<VL> VVL;
typedef vector<VVL> VVVL;
typedef vector<VPL> VVPL;
template<class T> T setmax(T& a, T b) {if (a < b) return a = b; return a;}
template<class T> T setmin(T& a, T b) {if (a < b) return a; return a = b;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T>
using indset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef vector<char> VC;
typedef vector<VC> VVC;
typedef vector<bool> VB;
typedef vector<VB> VVB;
void solve() {
int n, q;
ll S, T;
cin >> n >> q >> S >> T;
VL a(n+1);
for (ll& x : a) cin >> x;
VL d(n+1);
replr(i, 1, n) d[i] = a[i]-a[i-1];
ll sum = 0;
auto contribution = [&](int i) {
if (d[i] > 0) return -S*d[i];
return -T*d[i];
};
auto set = [&](int i, ll s) {
sum -= contribution(i);
d[i] = s;
sum += contribution(i);
};
replr(i, 1, n) sum += contribution(i);
while (q--) {
int l, r, x;
cin >> l >> r >> x;
set(l, d[l]+x);
if (r+1 <= n) set(r+1, d[r+1]-x);
cout << sum << endl;
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL), cout.tie(NULL);
/*freopen("mincross.in", "r", stdin); */
/*freopen("test.out", "w", stdout); */
int t = 1;
/*cin >> t; */
while (t--) solve();
}
