#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcount
const int N = 2e5 + 7;
int a[N], f[N];
void upd(int i, int x) { for (; i < N; i |= i + 1) f[i] += x; }
int get(int i) { int ans = 0; for (; i >= 0; i &= i + 1, --i) ans += f[i]; return ans; }
int n, q, s, t;
int getv(int i) {
if (i == n) return 0;
a[i] = get(i); a[i + 1] = get(i + 1);
if (a[i] < a[i + 1]) return - s * abs(a[i] - a[i + 1]);
else return t * abs(a[i] - a[i + 1]);
}
signed main() {
#ifdef HOME
freopen("input.txt", "r", stdin);
#else
ios_base::sync_with_stdio(0); cin.tie(0);
#endif
cin >> n >> q >> s >> t;
for (int i = 0; i <= n; ++i) { cin >> a[i]; upd(i, a[i]); upd(i + 1, -a[i]); }
int ans = 0;
for (int i = 0; i < n; ++i) ans += getv(i);
while (q--) {
int l, r, x; cin >> l >> r >> x;
ans -= getv(l - 1); ans -= getv(r);
upd(l, x); upd(r + 1, -x);
ans += getv(l - 1); ans += getv(r);
cout << ans << '\n';
}
}
