#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) { cerr << to_string(h); if(sizeof...(t)) cerr << ", "; DBG(t...); }
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
const int N = 2e5 + 3;
ll a[N];
struct fenwick_tree {
vector<int> bit;
void init(int n) {
bit.assign(n + 1, 0);
}
int sum(int i) {
int s = 0;
while (i > 0) {
s += bit[i];
i -= (i & (-i));
}
return s;
}
void add(int i, int val, int n) {
while (i > 0 && i <= n) {
bit[i] += val;
i += (i & (-i));
}
}
int get(int l, int r) {
return sum(r) - (l > 0 ? sum(l-1) : 0);
}
}; fenwick_tree fenwick;
void solve() {
ll n, q, s, t; cin >> n >> q >> s >> t;
fenwick.init(n);
for (int i = 1; i <= n+1; i++) cin >> a[i];
ll ans = 0;
for (int i = 2; i <= n+1; i++) {
if (a[i-1] < a[i])
ans -= (a[i]-a[i-1])*s;
else
ans += (a[i-1]-a[i])*t;
}
while (q--) {
ll l, r, x; cin >> l >> r >> x;
l++; r++;
if (a[l] > a[l-1])
ans += (a[l]-a[l-1])*s;
else ans -= (a[l-1]-a[l])*t;
if (r+1 <= n+1) {
if (a[r+1] > a[r])
ans += (a[r+1]-a[r])*s;
else ans -= (a[r]-a[r+1])*t;
}
for (int j = l; j <= r; j++)
a[j] += x;
if (a[l] > a[l-1])
ans -= (a[l]-a[l-1])*s;
else ans += (a[l-1]-a[l])*t;
if (r+1 <= n+1) {
if (a[r+1] > a[r])
ans -= (a[r+1]-a[r])*s;
else ans += (a[r]-a[r+1])*t;
}
cout << ans << "\n";
}
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0);
int t=1; //cin >> t;
while (t--) {
solve();
}
}
