#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fastio ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int main() {
fastio;
ll N, Q, S, T;
cin >> N >> Q >> S >> T;
vector<ll> altitudes(N + 1), diff(N + 2, 0), tempDiff(N + 1, 0);
ll temp = 0;
for (ll i = 0; i <= N; i++) {
cin >> altitudes[i];
if (i > 0) {
if (altitudes[i - 1] < altitudes[i])
temp += (altitudes[i - 1] - altitudes[i]) * S;
else
temp += (altitudes[i - 1] - altitudes[i]) * T;
tempDiff[i] = temp;
}
}
while (Q--) {
ll L, R, X;
cin >> L >> R >> X;
// Revert previous temperature contribution
if (L > 0) {
if (altitudes[L - 1] < altitudes[L])
temp -= (altitudes[L - 1] - altitudes[L]) * S;
else
temp -= (altitudes[L - 1] - altitudes[L]) * T;
}
if (R < N) {
if (altitudes[R] < altitudes[R + 1])
temp -= (altitudes[R] - altitudes[R + 1]) * S;
else
temp -= (altitudes[R] - altitudes[R + 1]) * T;
}
// Apply update with difference array
diff[L] += X;
diff[R + 1] -= X;
// Recalculate only the affected edges
altitudes[L] += X;
if (L > 0) {
if (altitudes[L - 1] < altitudes[L])
temp += (altitudes[L - 1] - altitudes[L]) * S;
else
temp += (altitudes[L - 1] - altitudes[L]) * T;
}
if (R < N) {
altitudes[R] += X;
if (altitudes[R] < altitudes[R + 1])
temp += (altitudes[R] - altitudes[R + 1]) * S;
else
temp += (altitudes[R] - altitudes[R + 1]) * T;
}
cout << temp << "\n";
}
return 0;
}
