#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;
using namespace chrono;
// mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
/*
template <class T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
*/
//***************** CONSTANTS *****************
//***************** GLOBAL VARIABLES *****************
//***************** AUXILIARY STRUCTS *****************
//***************** MAIN BODY *****************
void solve(){
int N, Q, S, T;
cin >> N >> Q >> S >> T;
int64_t A[N + 1];
for(int i = 0; i <= N; i++)
cin >> A[i];
int64_t diff[N], add[N];
int64_t ans = 0;
memset(diff, 0, sizeof diff);
memset(add, 0, sizeof add);
for(int i = 0; i < N; i++){
diff[i] = A[i] - A[i + 1];
add[i] = (diff[i] < 0 ? S : T);
ans += diff[i] * add[i];
}
for(int i = 0; i < Q; i++){
int l, r, x;
cin >> l >> r >> x;
ans -= diff[l - 1] * add[l - 1];
diff[l - 1] -= x;
add[l - 1] = (diff[l - 1] < 0 ? S : T);
ans += diff[l - 1] * add[l - 1];
if(r < N){
ans -= diff[r] * add[r];
diff[r] += x;
add[r] = (diff[r] < 0 ? S : T);
ans += diff[r] * add[r];
}
cout << ans << '\n';
}
}
//***************** *****************
int32_t main(){
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
#ifdef LOCAL
auto begin = high_resolution_clock::now();
#endif
int tc = 1;
// cin >> tc;
for (int t = 0; t < tc; t++)
solve();
#ifdef LOCAL
auto end = high_resolution_clock::now();
cout << fixed << setprecision(4);
cout << "Execution Time: " << duration_cast<duration<double>>(end - begin).count() << "seconds" << endl;
#endif
return 0;
}
/*
If code gives a WA, check for the following :
1. I/O format
2. Are you clearing all global variables in between tests if multitests are a thing
3. Can you definitively prove the logic
*/
