#include <bits/stdc++.h>
using namespace std;
# define int long long
# define fir first
# define sec second
# define pb push_back
const int cnst = 2e5+5;
bool mutipletestcase = 0;
//bool debug = false;
int n, q, s, t;
int all[cnst];
int arr[cnst];
int posi[cnst*4];
int lazy[cnst*4];
int merge(int a, int b) {
return a+b;
}
void build(int a, int b, int id) {
if(a == b) {
if(arr[a] < 0) posi[id] = s*abs(arr[a]);
else posi[id] = t*abs(arr[a]);
return;
}
int mid = (a+b)/2;
build(a, mid, id*2);
build(mid+1, b, id*2+1);
posi[id] = merge(posi[id*2], posi[id*2+1]);
}
void update(int a, int b, int id, int pos, int val) {
if(pos > b || pos < a) return;
// cerr << a << " " << b << " " << id << " " << pos << " " << val << endl;
if(a == pos && b == pos) {
if(arr[a] < 0) posi[id] = s*abs(arr[a]);
else posi[id] = t*abs(arr[a]);
return;
}
int mid =(a+b)/2;
if(pos <= mid) update(a, mid, id*2, pos, val);
else update(mid+1, b, id*2+1, pos, val);
posi[id] = merge(posi[id*2], posi[id*2+1]);
}
int get(int a, int b, int id, int from, int to) {
if(to < a || from > b) return 0;
if(from <= a && b <= to) return posi[id];
int mid = (a+b)/2;
return merge(get(a, mid, id*2, from, to), get(mid+1, b, id*2+1, from, to));
}
void solve() {
cin >> n >> q >> s >> t; s *= -1;
// all[0] = 0;
for(int i = 0 ; i<=n; i++) cin >> all[i];
for(int i = 1; i<=n; i++) arr[i] = all[i-1]-all[i];
build(1, n, 1);
// cerr << get(1, n, 1, 1, n) << endl;
// for(int i = 1; i<=n; i++) cerr << arr[i] << " "; cerr << endl;
// for(int i = 1; i<=n; i++) cerr << get(1, n, 1, i, i) << " "; cerr << endl; cerr << endl;
while(q--) {
int x, y, z; cin >> x >> y >> z;
arr[x] -= z;
arr[y+1] += z;
update(1, n, 1, x, 0);
// update(1, n, 1, y, 0);
update(1, n, 1, y+1, 0);
// for(int i = 1; i<=n; i++) cerr << arr[i] << " "; cerr << endl;
// for(int i = 1; i<=n; i++) cerr << get(1, n, 1, i, i) << " "; cerr << endl; cerr << endl;
cout << get(1, n, 1, 1, n) << endl;
}
}
signed main() {
ios_base::sync_with_stdio(false);
int t = 1;
if(mutipletestcase) cin >> t;
while(t--) solve();
}
