#include<bits/stdc++.h>
using namespace std;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, q, s, t;
cin >> n >> q >> s >> t;
s = -s;
vector<int>v(n + 1);
for(int i = 0;i <= n;++i){
cin >> v[i];
}
vector<long long>diff(n + 5);
long long temper = 0;
for(int i = 1;i <= n;++i){
diff[i] = v[i] - v[i - 1];
if(diff[i] < 0){
temper += (long long)t * -diff[i];
}
else{
temper += (long long)s * diff[i];
}
}
while(q--){
int l, r, x;
cin >> l >> r >> x;
if(diff[l] < 0){
temper -= (long long)t * -diff[l];
}
else{
temper -= (long long)s * diff[l];
}
if(diff[r + 1] < 0){
temper -= (long long)t * -diff[r + 1];
}
else{
temper -= (long long)s * diff[r + 1];
}
diff[l] += x;
if(r + 1 <= n)diff[r + 1] -= x;
if(diff[l] < 0){
temper += (long long)t * -diff[l];
}
else{
temper += (long long)s * diff[l];
}
if(diff[r + 1] < 0){
temper += (long long)t * -diff[r + 1];
}
else{
temper += (long long)s * diff[r + 1];
}
cout << temper << '\n';
}
}
