/*
Solution: Each query only updates the temperature change at 2 locations - on the left, and on the right.
So, use a BIT to handle range updates and point queries / update the temperature for each query.
Runtime: O((N+Q) * log(N)) with notable constant factor
*/
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define sz(x) ((int) x.size())
#define all(x) x.begin(), x.end()
#define debug if (true) cerr
using ll = long long;
const int MAXN = 2e5+5;
int N, Q;
int A[MAXN];
ll S, T;
ll currTemp;
struct BIT {
ll V[MAXN];
void upd(int i, ll v) {
for (; i <= N; i+=i&-i) {
V[i] += v;
}
}
ll getTemp(int i) {
if (i == 0 || i == N) return 0;
ll a = query(i), b = query(i+1);
if (a < b) return -S * (b-a);
else return T * (a-b);
}
void upd(int l, int r, ll v) {
currTemp -= getTemp(l-1);
currTemp -= getTemp(r);
upd(l, v);
upd(r+1, -v);
currTemp += getTemp(l-1);
currTemp += getTemp(r);
}
ll query(int i) {
ll r = 0;
for (; i > 0; i-=i&-i) {
r += V[i];
}
return r;
}
} bit;
void solve() {
cin >> N >> Q >> S >> T;
N++;
currTemp = 0;
rep(i, 1, N+1) {
cin >> A[i];
bit.upd(i, i, A[i]);
}
rep(i, 0, Q) {
int l, r;
ll x;
cin >> l >> r >> x;
l++, r++;
bit.upd(l, r, x);
cout << currTemp << '\n';
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
