#include <bits//stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less<long long>, rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag,
tree_order_statistics_node_update>
ordered_multiset;
#define ll long long
#define ld long double
#define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1))
#define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1))
#define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1))
#define lloop(m, h) for (auto l = m; l != h; l += (m < h ? 1 : -1))
#define iloop_(m, h, g) for (auto i = m; i < h; i += g)
#define jloop_(m, h, g) for (auto j = m; j < h; j += g)
#define kloop_(m, h, g) for (auto k = m; k < h; k += g)
#define lloop_(m, h, g) for (auto l = m; l < h; l += g)
#define getchar_unlocked _getchar_nolock // comment before submission
#define pll pair<ll, ll>
#define plll pair<ll, pll>
#define pllll pair<pll, pll>
#define vll vector<ll>
#define qll queue<ll>
#define dll deque<ll>
#define pqll priority_queue<ll>
#define gll greater<ll>
#define INF 1000000000000000
#define MOD1 1000000007
#define MOD2 998244353
#define MOD3 1000000009
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
ll n, q, x, y;
ll a[200005], cans;
struct node {
ll s, e, m, v, lazy = 0;
node *l, *r;
node (ll S, ll E) {
s = S, e = E, m = (S+E)>>1;
if (s == e) {v = a[s]; return;}
l = new node(s, m);
r = new node(m+1, e);
}
void prop() {
v += lazy;
if (s != e) {l->lazy += lazy; r->lazy += lazy;}
lazy = 0;
}
void upd(ll S, ll E, ll V) {
prop();
if (s == S && e == E) {lazy += V; return;}
if (E <= m) l->upd(S, E, V);
else if (S > m) r->upd(S, E, V);
else l->upd(S, m, V), r->upd(m+1, E, V);
}
ll qu(ll X) {
prop();
if (s == e) return v;
if (X <= m) return l->qu(X);
return r->qu(X);
}
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> q >> x >> y;
iloop(0, n+1) cin >> a[i];
iloop(0, n) cans += (a[i] < a[i+1] ? x*(a[i]-a[i+1]) : y*(a[i]-a[i+1]));
node root = node(0, n);
ll t1, t2, t3, x1, x2;
while (q--) {
cin >> t1 >> t2 >> t3;
x1 = root.qu(t1-1), x2 = root.qu(t1);
cans -= (x1 < x2 ? x*(x1-x2) : y*(x1-x2));
if (t2 != n) {
x1 = root.qu(t2), x2 = root.qu(t2+1);
cans -= (x1 < x2 ? x*(x1-x2) : y*(x1-x2));
}
root.upd(t1, t2, t3);
x1 = root.qu(t1-1), x2 = root.qu(t1);
cans += (x1 < x2 ? x*(x1-x2) : y*(x1-x2));
if (t2 != n) {
x1 = root.qu(t2), x2 = root.qu(t2+1);
cans += (x1 < x2 ? x*(x1-x2) : y*(x1-x2));
}
cout << cans << "\n";
}
}
