#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <deque>
#include <cmath>
#include <climits>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <functional>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <chrono>
#include <random>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define st first
#define nd second
#define pb push_back
const int inf = 1e9;
const ll infl = 1e18;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, q, s, t;
cin >> n >> q >> s >> t;
vector<ll> tab(n + 1);
vector<ll> diff(n); // diff[i] = tab[i+1] - tab[i]
ll wynik = 0;
for (int i = 0; i <= n; i++) {
cin >> tab[i];
}
for (int i = 0; i < n; i++) {
diff[i] = tab[i + 1] - tab[i];
if (diff[i] > 0) {
wynik -= s * diff[i];
} else {
wynik -= t * diff[i];
}
}
for (int i = 0; i < q; i++) {
int a, b;
ll v;
cin >> a >> b >> v;
ll poc = diff[a - 1];
diff[a - 1] += v;
ll new_a = diff[a - 1];
if (poc > 0) {
wynik += s * poc;
} else {
wynik += t * poc;
}
if (new_a > 0) {
wynik -= s * new_a;
} else {
wynik -= t * new_a;
}
if (b < n) {
ll kon = diff[b];
diff[b] -= v;
ll new_b = diff[b];
if (kon > 0) {
wynik += s * kon;
} else {
wynik += t * kon;
}
if (new_b > 0) {
wynik -= s * new_b;
} else {
wynik -= t * new_b;
}
}
cout << wynik << "\n";
}
return 0;
}
