#include <bits/stdc++.h>
using namespace std;
template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl
using ll = long long;
const int maxn = 1e6 + 5;
ll n,q,s,t;
ll a[maxn];
ll diff[maxn];
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>q>>s>>t;
for (int i=0; i<=n; i++) {
cin>>a[i];
}
auto get = [&](ll dx) {
if (dx>0) {
return -abs(dx)*s;
} else {
return +abs(dx)*t;
}
};
ll res = 0;
for (int i=1; i<=n; i++) {
diff[i] = a[i]-a[i-1];
res += get(diff[i]);
}
while (q--) {
ll l,r,x;
cin>>l>>r>>x;
res -= get(diff[l]);
diff[l] += x;
res += get(diff[l]);
if (r<n) {
res -= get(diff[r+1]);
diff[r+1] -= x;
res += get(diff[r+1]);
}
cout<<res<<"\n";
}
return 0;
}
